diff --git "a/modeling_qwen3_5.py" "b/modeling_qwen3_5.py"
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+++ "b/modeling_qwen3_5.py"
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+#                🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
+#           This file was automatically generated from src/transformers/models/quasar/modular_quasar.py.
+#               Do NOT edit this file manually as any edits will be overwritten by the generation of
+#             the file from the modular. If any change should be done, please apply the change to the
+#                          modular_quasar.py file directly. One of our CI enforces this.
+#                🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
+# Copyright 2025 The Qwen Team and The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from collections.abc import Callable
+from dataclasses import dataclass
+from typing import Any, Optional
+
+import torch
+import torch.nn.functional as F
+from torch import nn
+
+import transformers.initialization as init
+from transformers.activations import ACT2FN
+from transformers.modeling_utils import PreTrainedModel
+from transformers.utils import logging
+from transformers.modeling_outputs import (
+    BaseModelOutputWithPast,
+    BaseModelOutputWithPooling,
+    CausalLMOutputWithPast,
+    ModelOutput,
+)
+from configuration_qwen3_5 import QuasarConfig, QuasarTextConfig, QuasarVisionConfig
+
+# --- Cache ---
+try:
+    from transformers.cache_utils import Cache
+except ImportError:
+    from transformers.cache_utils import DynamicCache as Cache
+Caches = Cache  # alias used in type hints
+
+# --- GenerationMixin ---
+try:
+    from transformers.generation import GenerationMixin
+except ImportError:
+    from transformers.generation.utils import GenerationMixin
+
+# --- use_kernelized_func (dev-only decorator, no-op fallback) ---
+try:
+    from transformers.integrations import use_kernelized_func
+except ImportError:
+    def use_kernelized_func(fn):
+        def decorator(cls): return cls
+        return decorator
+
+# --- create_causal_mask ---
+try:
+    from transformers.masking_utils import create_causal_mask
+except ImportError:
+    def create_causal_mask(position_ids, attention_mask, cache_position, config, past_key_values=None, **kwargs):
+        import torch
+        bsz, seq_len = position_ids.shape
+        device = position_ids.device
+        causal = torch.tril(torch.ones(seq_len, seq_len, device=device)).view(1, 1, seq_len, seq_len)
+        return (1.0 - causal) * torch.finfo(torch.float32).min
+
+# --- FlashAttentionKwargs ---
+try:
+    from transformers.modeling_flash_attention_utils import FlashAttentionKwargs
+except ImportError:
+    class FlashAttentionKwargs(dict): pass
+
+# --- GradientCheckpointingLayer ---
+import torch.nn as nn
+class GradientCheckpointingLayer(nn.Module): pass
+
+# --- ROPE_INIT_FUNCTIONS, dynamic_rope_update ---
+try:
+    from transformers.modeling_rope_utils import ROPE_INIT_FUNCTIONS, dynamic_rope_update
+except ImportError:
+    ROPE_INIT_FUNCTIONS = {}
+    def dynamic_rope_update(fn): return fn
+
+# --- ALL_ATTENTION_FUNCTIONS ---
+try:
+    from transformers.modeling_utils import ALL_ATTENTION_FUNCTIONS
+except ImportError:
+    class _AttentionFunctionRegistry(dict):
+        def get_interface(self, impl, default=None): return self.get(impl, default)
+    ALL_ATTENTION_FUNCTIONS = _AttentionFunctionRegistry()
+
+# --- Unpack, TransformersKwargs ---
+try:
+    from transformers.processing_utils import Unpack
+except ImportError:
+    try:
+        from typing_extensions import Unpack
+    except ImportError:
+        class _UnpackMeta(type):
+            def __getitem__(cls, item): return cls
+        class Unpack(metaclass=_UnpackMeta): pass
+
+try:
+    from transformers.utils import TransformersKwargs
+except ImportError:
+    class TransformersKwargs(dict): pass
+
+# --- auto_docstring, can_return_tuple, torch_compilable_check ---
+try:
+    from transformers.utils import auto_docstring
+except ImportError:
+    def auto_docstring(*args, **kwargs):
+        if len(args) == 1 and callable(args[0]): return args[0]
+        def decorator(fn): return fn
+        return decorator
+
+try:
+    from transformers.utils import can_return_tuple
+except ImportError:
+    def can_return_tuple(fn): return fn
+
+try:
+    from transformers.utils import torch_compilable_check
+except ImportError:
+    def torch_compilable_check(*args, **kwargs): pass
+
+# --- is_flash_attention_requested, maybe_autocast, merge_with_config_defaults ---
+try:
+    from transformers.utils.generic import is_flash_attention_requested
+except ImportError:
+    def is_flash_attention_requested(config): return getattr(config, "_attn_implementation", "eager") == "flash_attention_2"
+
+try:
+    from transformers.utils.generic import maybe_autocast
+except ImportError:
+    from contextlib import contextmanager
+    @contextmanager
+    def maybe_autocast(*args, **kwargs): yield
+
+try:
+    from transformers.utils.generic import merge_with_config_defaults
+except ImportError:
+    def merge_with_config_defaults(fn): return fn
+
+# --- is_causal_conv1d_available, is_flash_linear_attention_available ---
+try:
+    from transformers.utils.import_utils import is_causal_conv1d_available, is_flash_linear_attention_available
+except ImportError:
+    def is_causal_conv1d_available(): return True
+    def is_flash_linear_attention_available(): return True
+
+# --- capture_outputs ---
+try:
+    from transformers.utils.output_capturing import capture_outputs
+except ImportError:
+    def capture_outputs(fn): return fn
+
+
+from causal_conv1d import causal_conv1d_fn, causal_conv1d_update
+from fla.modules import FusedRMSNormGated
+from fla.ops.gated_delta_rule import chunk_gated_delta_rule, fused_recurrent_gated_delta_rule
+
+logger = logging.get_logger(__name__)
+
+
+
+class QuasarDynamicCache:
+    """
+    A dynamic cache that can handle both the attention cache (which has a seq_len dimension) and the linear attention
+    cache (which has a constant shape regardless of seq_len).
+
+    This cache has two sets of lists of tensors: `key_cache` and `value_cache` for attention cache and `conv_states`
+    and `ssm_states` for gated deltanet cache. Each of these lists has `num_layers` tensors. The expected shape for each tensor
+    For attention layers, `key_cache` and `value_cache` have a shape of `(batch_size, num_heads, seq_len, head_dim)`,
+    while `conv_states` and `ssm_states` have a shape of `(batch_size, 0)` (empty tensors).
+    For linear attention layers, `key_cache` and `value_cache` have a shape of `(batch_size, 0)` (empty tensors),
+    while `conv_states` represents the convolution state and has a shape of `(batch_size, d_inner, d_conv)`,
+    and `recurrent_states` represents the recurrent state and has a shape of `(batch_size, d_inner, d_state)`.
+    """
+
+    is_compileable = False
+
+    def __init__(self, config: QuasarConfig):
+        super().__init__()
+        self.layer_types = config.layer_types
+        self.transformer_layers = [
+            i for i in range(config.num_hidden_layers) if self.layer_types[i] == "full_attention"
+        ]
+        self.last_linear_layer = len(self.layer_types) - 1 - self.layer_types[::-1].index("linear_attention")
+
+        # Initialize everything to None -> will be lazy initialized to allow multi-gpu (device_map) inference
+        self.conv_states = [None for _ in range(config.num_hidden_layers)]
+        self.recurrent_states = [None for _ in range(config.num_hidden_layers)]
+        self.key_cache = [None for _ in range(config.num_hidden_layers)]
+        self.value_cache = [None for _ in range(config.num_hidden_layers)]
+        
+        # Used for FSDP Activation Checkpointing safety
+        self.original_conv_states = [None for _ in range(config.num_hidden_layers)]
+        self.original_recurrent_states = [None for _ in range(config.num_hidden_layers)]
+        self.is_recomputing = False
+
+    def __len__(self):
+        return len(self.layer_types)
+
+    def __getitem__(self, layer_idx: int) -> dict[str, Any]:
+        if self.is_recomputing:
+            return {
+                "conv_state": self.original_conv_states[layer_idx],
+                "recurrent_state": self.original_recurrent_states[layer_idx],
+            }
+        else:
+            return {
+                "conv_state": self.conv_states[layer_idx],
+                "recurrent_state": self.recurrent_states[layer_idx],
+            }
+
+    def update(
+        self,
+        key_states: torch.Tensor | None = None,
+        value_states: torch.Tensor | None = None,
+        layer_idx: int | None = None,
+        cache_kwargs: dict[str, Any] | None = None,
+        recurrent_state: torch.Tensor | None = None,
+        conv_state: Any | None = None,
+        offset: int | None = None,
+    ) -> tuple[torch.Tensor, torch.Tensor] | None:
+        if key_states is not None:
+            if self.key_cache[layer_idx] is None:
+                self.key_cache[layer_idx] = key_states
+                self.value_cache[layer_idx] = value_states
+            else:
+                self.key_cache[layer_idx] = torch.cat([self.key_cache[layer_idx], key_states], dim=2)
+                self.value_cache[layer_idx] = torch.cat([self.value_cache[layer_idx], value_states], dim=2)
+            return self.key_cache[layer_idx], self.value_cache[layer_idx]
+
+        if recurrent_state is not None or conv_state is not None:
+            if not self.is_recomputing:
+                # Save original states BEFORE overwriting them
+                self.original_recurrent_states[layer_idx] = self.recurrent_states[layer_idx]
+                self.original_conv_states[layer_idx] = self.conv_states[layer_idx]
+                
+                # Update current states
+                if recurrent_state is not None:
+                    self.recurrent_states[layer_idx] = recurrent_state
+                if conv_state is not None:
+                    self.conv_states[layer_idx] = conv_state
+            return None
+
+    def reorder_cache(self, beam_idx: torch.LongTensor):
+        """Reorders the cache for beam search, given the selected beam indices."""
+        for layer_idx in range(len(self.key_cache)):
+            if self.key_cache[layer_idx] is not None:
+                device = self.key_cache[layer_idx].device
+                beam_idx = beam_idx.to(device)
+                self.key_cache[layer_idx] = self.key_cache[layer_idx].index_select(0, beam_idx)
+                self.value_cache[layer_idx] = self.value_cache[layer_idx].index_select(0, beam_idx)
+
+            if self.conv_states[layer_idx] is not None:
+                device = self.conv_states[layer_idx].device
+                beam_idx = beam_idx.to(device)
+                self.conv_states[layer_idx] = self.conv_states[layer_idx].index_select(0, beam_idx)
+                self.recurrent_states[layer_idx] = self.recurrent_states[layer_idx].index_select(0, beam_idx)
+
+    def get_seq_length(self, layer_idx: int | None = 0) -> int:
+        """Returns the sequence length of the cached states. A layer index can be optionally passed."""
+        # take any layer that contains cache and not empty tensor
+        layer_idx = self.transformer_layers[0] if layer_idx not in self.transformer_layers else layer_idx
+        if len(self.key_cache) <= layer_idx or self.key_cache[layer_idx] is None:
+            return 0
+        return self.key_cache[layer_idx].shape[-2]
+
+    def get_mask_sizes(self, cache_position: torch.Tensor, layer_idx: int) -> tuple[int, int]:
+        """
+        Return a tuple (kv_length, kv_offset) corresponding to the length and offset that will be returned for
+        the given layer at `layer_idx`.
+        The masks are then prepared according to the given lengths (kv_length, kv_offset) and patterns for each layer.
+        """
+        kv_offset = 0
+        query_length = cache_position.shape[0]
+        past_seen_tokens = self.get_seq_length(layer_idx)
+        kv_length = query_length + past_seen_tokens
+        return kv_length, kv_offset
+
+    @property
+    def has_previous_state(self):
+        """We have a previous state if the last linear (conv) layer was already updated."""
+        return self.conv_states[self.last_linear_layer] is not None
+
+
+class QuasarVisionRotaryEmbedding(nn.Module):
+    inv_freq: torch.Tensor  # fix linting for `register_buffer`
+
+    def __init__(self, dim: int, theta: float = 10000.0) -> None:
+        super().__init__()
+        self.dim = dim
+        self.theta = theta
+        inv_freq = 1.0 / (theta ** (torch.arange(0, dim, 2, dtype=torch.float) / dim))
+        self.register_buffer("inv_freq", inv_freq, persistent=False)
+
+    def forward(self, seqlen: int) -> torch.Tensor:
+        seq = torch.arange(seqlen, device=self.inv_freq.device, dtype=self.inv_freq.dtype)
+        freqs = torch.outer(seq, self.inv_freq)
+        return freqs
+
+
+class QuasarTextRotaryEmbedding(nn.Module):
+    inv_freq: torch.Tensor  # fix linting for `register_buffer`
+
+    def __init__(self, config: QuasarTextConfig, device=None):
+        super().__init__()
+        self.max_seq_len_cached = config.max_position_embeddings
+        self.original_max_seq_len = config.max_position_embeddings
+
+        self.config = config
+
+        self.rope_type = self.config.rope_parameters["rope_type"]
+        rope_init_fn: Callable = self.compute_default_rope_parameters
+        if self.rope_type != "default":
+            rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type]
+        inv_freq, self.attention_scaling = rope_init_fn(self.config, device)
+
+        self.register_buffer("inv_freq", inv_freq, persistent=False)
+        self.register_buffer("original_inv_freq", inv_freq.clone(), persistent=False)
+        self.mrope_section = config.rope_parameters.get("mrope_section", [11, 11, 10])
+
+    @staticmethod
+    def compute_default_rope_parameters(
+        config: QuasarTextConfig | None = None,
+        device: Optional["torch.device"] = None,
+        seq_len: int | None = None,
+    ) -> tuple["torch.Tensor", float]:
+        """
+        Computes the inverse frequencies according to the original RoPE implementation
+        Args:
+            config ([`~transformers.PreTrainedConfig`]):
+                The model configuration.
+            device (`torch.device`):
+                The device to use for initialization of the inverse frequencies.
+            seq_len (`int`, *optional*):
+                The current sequence length. Unused for this type of RoPE.
+        Returns:
+            Tuple of (`torch.Tensor`, `float`), containing the inverse frequencies for the RoPE embeddings and the
+            post-processing scaling factor applied to the computed cos/sin (unused in this type of RoPE).
+        """
+        base = config.rope_parameters["rope_theta"]
+        partial_rotary_factor = config.rope_parameters.get("partial_rotary_factor", 1.0)
+        head_dim = getattr(config, "head_dim", None) or config.hidden_size // config.num_attention_heads
+        dim = int(head_dim * partial_rotary_factor)
+
+        attention_factor = 1.0  # Unused in this type of RoPE
+
+        # Compute the inverse frequencies
+        inv_freq = 1.0 / (
+            base ** (torch.arange(0, dim, 2, dtype=torch.int64).to(device=device, dtype=torch.float) / dim)
+        )
+        return inv_freq, attention_factor
+
+    @torch.no_grad()
+    @dynamic_rope_update  # power user: used with advanced RoPE types (e.g. dynamic rope)
+    def forward(self, x, position_ids):
+        # In contrast to other models, Quasar has different position ids for the grids
+        # So we expand the inv_freq to shape (3, ...)
+        if position_ids.ndim == 2:
+            position_ids = position_ids[None, ...].expand(3, position_ids.shape[0], -1)
+        inv_freq_expanded = self.inv_freq[None, None, :, None].float().expand(3, position_ids.shape[1], -1, 1)
+        position_ids_expanded = position_ids[:, :, None, :].float()  # shape (3, bs, 1, positions)
+
+        device_type = x.device.type if isinstance(x.device.type, str) and x.device.type != "mps" else "cpu"
+        with maybe_autocast(device_type=device_type, enabled=False):  # Force float32
+            freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(2, 3)
+            freqs = self.apply_interleaved_mrope(freqs, self.mrope_section)
+            emb = torch.cat((freqs, freqs), dim=-1)
+            cos = emb.cos() * self.attention_scaling
+            sin = emb.sin() * self.attention_scaling
+
+        return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)
+
+    def apply_interleaved_mrope(self, freqs, mrope_section):
+        """Apply interleaved MRoPE to 3D rotary embeddings.
+        Reorganizes frequency layout from chunked [TTT...HHH...WWW] to
+        interleaved [THWTHWTHW...TT], preserving frequency continuity.
+        args:
+            x: (3, bs, seq_len, head_dim // 2)
+            mrope_section: (3,)
+        returns:
+            x_t: (bs, seq_len, head_dim // 2)
+        """
+        freqs_t = freqs[0]  # just overwrite the first dimension T
+        for dim, offset in enumerate((1, 2), start=1):  # H, W
+            length = mrope_section[dim] * 3
+            idx = slice(offset, length, 3)
+            freqs_t[..., idx] = freqs[dim, ..., idx]
+        return freqs_t
+
+
+class QuasarRMSNormGated(nn.Module):
+    def __init__(self, hidden_size, eps=1e-6, **kwargs):
+        super().__init__()
+        self.weight = nn.Parameter(torch.ones(hidden_size))
+        self.variance_epsilon = eps
+
+    def forward(self, hidden_states, gate=None):
+        input_dtype = hidden_states.dtype
+        hidden_states = hidden_states.to(torch.float32)
+        variance = hidden_states.pow(2).mean(-1, keepdim=True)
+        # Norm before gate
+        hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
+        hidden_states = self.weight * hidden_states.to(input_dtype)
+        hidden_states = hidden_states * F.silu(gate.to(torch.float32))
+
+        return hidden_states.to(input_dtype)
+
+
+def apply_mask_to_padding_states(hidden_states, attention_mask):
+    """
+    Tunes out the hidden states for padding tokens, see https://github.com/state-spaces/mamba/issues/66
+    """
+    # NOTE: attention mask is a 2D boolean tensor
+    if attention_mask is not None and attention_mask.shape[1] > 1 and attention_mask.shape[0] > 1:
+        dtype = hidden_states.dtype
+        hidden_states = (hidden_states * attention_mask[:, :, None]).to(dtype)
+
+    return hidden_states
+
+def l2norm(x: torch.FloatTensor, dim: int = -1, eps: float = 1e-6):
+    """This function is intended to align with the l2norm implementation in the FLA library."""
+    inv_norm = torch.rsqrt((x * x).sum(dim=dim, keepdim=True) + eps)
+    return x * inv_norm
+
+class QuasarGatedDeltaNet(nn.Module):
+    def __init__(self, config: QuasarConfig, layer_idx: int):
+        super().__init__()
+        self.hidden_size = config.hidden_size
+        self.num_v_heads = config.linear_num_value_heads
+        self.num_k_heads = config.linear_num_key_heads
+        self.head_k_dim = config.linear_key_head_dim
+        self.head_v_dim = config.linear_value_head_dim
+        self.key_dim = self.head_k_dim * self.num_k_heads
+        self.value_dim = self.head_v_dim * self.num_v_heads
+
+        self.conv_kernel_size = config.linear_conv_kernel_dim
+        self.layer_idx = layer_idx
+        self.activation = config.hidden_act
+        self.act = ACT2FN[config.hidden_act]
+        self.layer_norm_epsilon = config.rms_norm_eps
+
+        # QKV
+        self.conv_dim = self.key_dim * 2 + self.value_dim
+        self.conv1d = nn.Conv1d(
+            in_channels=self.conv_dim,
+            out_channels=self.conv_dim,
+            bias=False,
+            kernel_size=self.conv_kernel_size,
+            groups=self.conv_dim,
+            padding=self.conv_kernel_size - 1,
+        )
+
+        # time step projection (discretization)
+        # instantiate once and copy inv_dt in init_weights of PretrainedModel
+        self.dt_bias = nn.Parameter(torch.ones(self.num_v_heads))
+
+        A = torch.empty(self.num_v_heads).uniform_(0, 16)
+        self.A_log = nn.Parameter(torch.log(A))
+
+        self.norm = FusedRMSNormGated(
+            self.head_v_dim,
+            eps=self.layer_norm_epsilon,
+            activation=self.activation,
+            # device handling fixed
+            dtype=config.torch_dtype if hasattr(config, "torch_dtype") and config.torch_dtype is not None else torch.get_default_dtype(),
+        )
+
+        self.out_proj = nn.Linear(self.value_dim, self.hidden_size, bias=False)
+
+        self.causal_conv1d_fn = causal_conv1d_fn
+        self.causal_conv1d_update = causal_conv1d_update
+        self.chunk_gated_delta_rule = chunk_gated_delta_rule
+        self.recurrent_gated_delta_rule = fused_recurrent_gated_delta_rule
+
+        self.in_proj_qkv = nn.Linear(self.hidden_size, self.key_dim * 2 + self.value_dim, bias=False)
+        self.in_proj_z = nn.Linear(self.hidden_size, self.value_dim, bias=False)
+        self.in_proj_b = nn.Linear(self.hidden_size, self.num_v_heads, bias=False)
+        self.in_proj_a = nn.Linear(self.hidden_size, self.num_v_heads, bias=False)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        cache_params: QuasarDynamicCache | None = None,
+        cache_position: torch.LongTensor | None = None,
+        attention_mask: torch.Tensor | None = None,
+    ):
+        hidden_states = apply_mask_to_padding_states(hidden_states, attention_mask)
+
+        # Set up dimensions for reshapes later
+        batch_size, seq_len, _ = hidden_states.shape
+
+        use_precomputed_states = (
+            cache_params is not None
+            and cache_params.has_previous_state
+            and seq_len == 1
+            and cache_position is not None
+        )
+
+        # getting projected states from cache if it exists
+        if cache_params is not None:
+            conv_state = cache_params.conv_states[self.layer_idx]
+            recurrent_state = cache_params.recurrent_states[self.layer_idx]
+
+        mixed_qkv = self.in_proj_qkv(hidden_states)
+        mixed_qkv = mixed_qkv.transpose(1, 2)
+
+        z = self.in_proj_z(hidden_states)
+        z = z.reshape(batch_size, seq_len, -1, self.head_v_dim)
+
+        b = self.in_proj_b(hidden_states)
+        a = self.in_proj_a(hidden_states)
+
+        if use_precomputed_states:
+            # 2. Convolution sequence transformation
+            # NOTE: the conv state is updated in `causal_conv1d_update`
+            mixed_qkv = self.causal_conv1d_update(
+                mixed_qkv,
+                conv_state,
+                self.conv1d.weight.squeeze(1),
+                self.conv1d.bias,
+                self.activation,
+            )
+        else:
+            if cache_params is not None:
+                conv_state = F.pad(mixed_qkv, (self.conv_kernel_size - mixed_qkv.shape[-1], 0))
+                cache_params.conv_states[self.layer_idx] = conv_state
+            if self.causal_conv1d_fn is not None:
+                mixed_qkv = self.causal_conv1d_fn(
+                    x=mixed_qkv,
+                    weight=self.conv1d.weight.squeeze(1),
+                    bias=self.conv1d.bias,
+                    activation=self.activation,
+                    seq_idx=None,
+                )
+            else:
+                mixed_qkv = F.silu(self.conv1d(mixed_qkv)[:, :, :seq_len])
+
+        mixed_qkv = mixed_qkv.transpose(1, 2)
+        query, key, value = torch.split(
+            mixed_qkv,
+            [
+                self.key_dim,
+                self.key_dim,
+                self.value_dim,
+            ],
+            dim=-1,
+        )
+
+        query = query.reshape(batch_size, seq_len, -1, self.head_k_dim)
+        key = key.reshape(batch_size, seq_len, -1, self.head_k_dim)
+        value = value.reshape(batch_size, seq_len, -1, self.head_v_dim)
+
+        beta = b.sigmoid()
+        # If the model is loaded in fp16, without the .float() here, A might be -inf
+        g = -self.A_log.float().exp() * F.softplus(a.float() + self.dt_bias)
+        if self.num_v_heads // self.num_k_heads > 1:
+            query = query.repeat_interleave(self.num_v_heads // self.num_k_heads, dim=2)
+            key = key.repeat_interleave(self.num_v_heads // self.num_k_heads, dim=2)
+
+        if not use_precomputed_states:
+            core_attn_out, last_recurrent_state = self.chunk_gated_delta_rule(
+                query,
+                key,
+                value,
+                g=g,
+                beta=beta,
+                initial_state=None,
+                output_final_state=cache_params is not None,
+                use_qk_l2norm_in_kernel=True,
+            )
+
+        else:
+            core_attn_out, last_recurrent_state = self.recurrent_gated_delta_rule(
+                query,
+                key,
+                value,
+                g=g,
+                beta=beta,
+                initial_state=recurrent_state,
+                output_final_state=cache_params is not None,
+                use_qk_l2norm_in_kernel=True,
+            )
+
+        # Update cache
+        if cache_params is not None:
+            cache_params.recurrent_states[self.layer_idx] = last_recurrent_state
+
+        # reshape input data into 2D tensor
+        core_attn_out = core_attn_out.reshape(-1, self.head_v_dim)
+        z = z.reshape(-1, self.head_v_dim)
+        core_attn_out = self.norm(core_attn_out, z)
+        core_attn_out = core_attn_out.reshape(batch_size, seq_len, -1)
+
+        output = self.out_proj(core_attn_out)
+        return output
+
+
+def rotate_half(x):
+    """Rotates half the hidden dims of the input."""
+    x1 = x[..., : x.shape[-1] // 2]
+    x2 = x[..., x.shape[-1] // 2 :]
+    return torch.cat((-x2, x1), dim=-1)
+
+
+# Adapted from transformers.models.glm.modular_glm.apply_rotary_pos_emb
+def apply_rotary_pos_emb(q, k, cos, sin, unsqueeze_dim=1):
+    """Applies Rotary Position Embedding to the query and key tensors.
+
+    Removes the interleaving of cos and sin from GLM
+
+    Args:
+        q (`torch.Tensor`): The query tensor.
+        k (`torch.Tensor`): The key tensor.
+        cos (`torch.Tensor`): The cosine part of the rotary embedding.
+        sin (`torch.Tensor`): The sine part of the rotary embedding.
+        unsqueeze_dim (`int`, *optional*, defaults to 1):
+            The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
+            sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
+            that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
+            k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
+            cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
+            the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
+    Returns:
+        `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
+    """
+    cos = cos.unsqueeze(unsqueeze_dim)
+    sin = sin.unsqueeze(unsqueeze_dim)
+
+    # Keep half or full tensor for later concatenation
+    rotary_dim = cos.shape[-1]
+    q_rot, q_pass = q[..., :rotary_dim], q[..., rotary_dim:]
+    k_rot, k_pass = k[..., :rotary_dim], k[..., rotary_dim:]
+
+    # Apply rotary embeddings on the first half or full tensor
+    q_embed = (q_rot * cos) + (rotate_half(q_rot) * sin)
+    k_embed = (k_rot * cos) + (rotate_half(k_rot) * sin)
+
+    # Concatenate back to full shape
+    q_embed = torch.cat([q_embed, q_pass], dim=-1)
+    k_embed = torch.cat([k_embed, k_pass], dim=-1)
+    return q_embed, k_embed
+
+
+def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
+    """
+    This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
+    num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
+    """
+    batch, num_key_value_heads, slen, head_dim = hidden_states.shape
+    if n_rep == 1:
+        return hidden_states
+    hidden_states = hidden_states[:, :, None, :, :].expand(batch, num_key_value_heads, n_rep, slen, head_dim)
+    return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim)
+
+
+def eager_attention_forward(
+    module: nn.Module,
+    query: torch.Tensor,
+    key: torch.Tensor,
+    value: torch.Tensor,
+    attention_mask: torch.Tensor | None,
+    scaling: float,
+    dropout: float = 0.0,
+    **kwargs: Unpack[TransformersKwargs],
+):
+    """Memory-efficient attention using SDPA kernel. Math fallback disabled to prevent OOM on long sequences."""
+    key_states = repeat_kv(key, module.num_key_value_groups)
+    value_states = repeat_kv(value, module.num_key_value_groups)
+
+    # Convert additive mask to bool causal mask compatible with SDPA
+    if attention_mask is not None:
+        # SDPA expects 0 = attend, 1 = mask (True = ignore)
+        attn_mask = attention_mask < -1  # additive mask: large negative = masked
+    else:
+        attn_mask = None
+
+    # Strictly ban the math backend to prevent OOM on 2M-token KV caches
+    with torch.backends.cuda.sdp_kernel(enable_flash=True, enable_mem_efficient=True, enable_math=False):
+        attn_output = F.scaled_dot_product_attention(
+            query, key_states, value_states,
+            attn_mask=attn_mask,
+            dropout_p=dropout if module.training else 0.0,
+            scale=scaling,
+            is_causal=(attn_mask is None),
+        )
+
+    attn_output = attn_output.transpose(1, 2).contiguous()
+    return attn_output, None  # no attn_weights returned (incompatible with fused kernels)
+
+
+
+@use_kernelized_func(apply_rotary_pos_emb)
+class QuasarAttention(nn.Module):
+    """Multi-headed attention from 'Attention Is All You Need' paper"""
+
+    def __init__(self, config: QuasarConfig, layer_idx: int):
+        super().__init__()
+        self.config = config
+        self.layer_idx = layer_idx
+        self.head_dim = getattr(config, "head_dim", config.hidden_size // config.num_attention_heads)
+        self.num_key_value_groups = config.num_attention_heads // config.num_key_value_heads
+        self.scaling = self.head_dim**-0.5
+        self.attention_dropout = config.attention_dropout
+        self.is_causal = True
+        self.q_proj = nn.Linear(
+            config.hidden_size, config.num_attention_heads * self.head_dim * 2, bias=config.attention_bias
+        )
+        self.k_proj = nn.Linear(
+            config.hidden_size, config.num_key_value_heads * self.head_dim, bias=config.attention_bias
+        )
+        self.v_proj = nn.Linear(
+            config.hidden_size, config.num_key_value_heads * self.head_dim, bias=config.attention_bias
+        )
+        self.o_proj = nn.Linear(
+            config.num_attention_heads * self.head_dim, config.hidden_size, bias=config.attention_bias
+        )
+        self.q_norm = QuasarRMSNorm(self.head_dim, eps=config.rms_norm_eps)  # unlike olmo, only on the head dim!
+        self.k_norm = QuasarRMSNorm(self.head_dim, eps=config.rms_norm_eps)  # thus post q_norm does not need reshape
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        position_embeddings: tuple[torch.Tensor, torch.Tensor],
+        attention_mask: torch.Tensor | None,
+        past_key_values: Cache | None = None,
+        cache_position: torch.LongTensor | None = None,
+        **kwargs: Unpack[FlashAttentionKwargs],
+    ) -> tuple[torch.Tensor, torch.Tensor | None]:
+        input_shape = hidden_states.shape[:-1]
+        hidden_shape = (*input_shape, -1, self.head_dim)
+
+        query_states, gate = torch.chunk(
+            self.q_proj(hidden_states).view(*input_shape, -1, self.head_dim * 2), 2, dim=-1
+        )
+        gate = gate.reshape(*input_shape, -1)
+
+        query_states = self.q_norm(query_states.view(hidden_shape)).transpose(1, 2)
+        key_states = self.k_norm(self.k_proj(hidden_states).view(hidden_shape)).transpose(1, 2)
+        value_states = self.v_proj(hidden_states).view(hidden_shape).transpose(1, 2)
+
+        cos, sin = position_embeddings
+        if not getattr(self.config, "use_nope", False):
+            query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin)
+
+        if past_key_values is not None:
+            # sin and cos are specific to RoPE models; cache_position needed for the static cache
+            cache_kwargs = {"sin": sin, "cos": cos, "cache_position": cache_position}
+            key_states, value_states = past_key_values.update(key_states, value_states, self.layer_idx, cache_kwargs)
+
+        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
+            self.config._attn_implementation, eager_attention_forward
+        )
+
+        attn_output, attn_weights = attention_interface(
+            self,
+            query_states,
+            key_states,
+            value_states,
+            attention_mask,
+            dropout=0.0 if not self.training else self.attention_dropout,
+            scaling=self.scaling,
+            **kwargs,
+        )
+
+        attn_output = attn_output.reshape(*input_shape, -1).contiguous()
+        attn_output = attn_output * torch.sigmoid(gate)
+
+        attn_output = self.o_proj(attn_output)
+        return attn_output, attn_weights
+
+
+class QuasarMLP(nn.Module):
+    def __init__(self, config: QuasarConfig, intermediate_size: int):
+        super().__init__()
+        self.config = config
+        self.hidden_size = config.hidden_size
+        self.intermediate_size = intermediate_size
+        self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
+        self.up_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
+        self.down_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=False)
+        self.act_fn = ACT2FN[config.hidden_act]
+
+    def forward(self, x):
+        down_proj = self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
+        return down_proj
+
+
+class QuasarRMSNorm(nn.Module):
+    def __init__(self, dim: int, eps: float = 1e-6):
+        super().__init__()
+        self.eps = eps
+        self.weight = nn.Parameter(torch.zeros(dim))
+
+    def _norm(self, x):
+        return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps)
+
+    def forward(self, x):
+        output = self._norm(x.float())
+        # Llama does x.to(float16) * w whilst Quasar is (x * w).to(float16)
+        # See https://github.com/huggingface/transformers/pull/29402
+        output = output * (1.0 + self.weight.float())
+        return output.type_as(x)
+
+    def extra_repr(self):
+        return f"{tuple(self.weight.shape)}, eps={self.eps}"
+
+
+class QuasarGatedLinearAttention(nn.Module):
+    def __init__(self, config: QuasarConfig, layer_idx: int):
+        super().__init__()
+        # Use config.text_config if it exists (for multimodal wrapper)
+        self.config = getattr(config, "text_config", config)
+        self.layer_idx = layer_idx
+        
+        hidden_size = self.config.hidden_size
+        num_heads = self.config.num_attention_heads
+        num_kv_heads = self.config.num_key_value_heads
+        head_dim = getattr(self.config, "head_dim", hidden_size // num_heads)
+        
+        expand_k = (num_kv_heads * head_dim) / hidden_size
+        expand_v = (num_kv_heads * head_dim) / hidden_size
+
+        from fla.layers.gla import GatedLinearAttention
+        # We host the GLA module under .gla to match the naming in our Distillation checkpoints
+        self.gla = GatedLinearAttention(
+            mode='chunk',
+            hidden_size=hidden_size,
+            expand_k=expand_k,
+            expand_v=expand_v,
+            num_heads=num_heads,
+            num_kv_heads=num_kv_heads,
+            use_short_conv=False,
+            layer_idx=layer_idx
+        )
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        position_embeddings: tuple[torch.Tensor, torch.Tensor],
+        attention_mask: torch.Tensor | None,
+        past_key_values: Cache | None = None,
+        cache_position: torch.LongTensor | None = None,
+        **kwargs: Unpack[FlashAttentionKwargs],
+    ) -> tuple[torch.Tensor, torch.Tensor | None]:
+        
+        outputs = self.gla(
+            hidden_states=hidden_states,
+            attention_mask=attention_mask,
+            past_key_values=past_key_values,
+            use_cache=past_key_values is not None,
+            output_attentions=False,
+        )
+        
+        attn_output = outputs[0]
+        
+        return attn_output, None
+
+
+class QuasarDecoderLayer(GradientCheckpointingLayer):
+    def __init__(self, config: QuasarTextConfig, layer_idx: int):
+        super().__init__()
+        self.hidden_size = config.hidden_size
+        self.config = config
+        self.layer_type = config.layer_types[layer_idx]
+        if self.layer_type == "linear_attention":
+            self.linear_attn = QuasarGatedDeltaNet(config, layer_idx)
+        elif self.layer_type == "full_attention":
+            # Check both root and text_config for the GLA flag
+            # We also check the model_type as a fallback signal
+            # Check for GLA flag in both root config and text_config
+            text_config = getattr(config, "text_config", config)
+            use_gla = getattr(text_config, "use_gla", False)
+            
+            # Final fallback: if we see 'linear_attention' in types, or if use_gla is globally true, 
+            # we likely want GLA for these 'full_attention' layers as well (hybrid/distilled models)
+            if not use_gla and "linear_attention" in getattr(text_config, "layer_types", []):
+                use_gla = True
+
+            if use_gla:
+                print(f"  [L{layer_idx}] Initializing Quasar Gated-Linear Attention...")
+                self.self_attn = QuasarGatedLinearAttention(config, layer_idx)
+            else:
+                self.self_attn = QuasarAttention(config, layer_idx)
+        self.mlp = QuasarMLP(config, config.intermediate_size)
+        self.input_layernorm = QuasarRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
+        self.post_attention_layernorm = QuasarRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        position_embeddings: tuple[torch.Tensor, torch.Tensor],
+        attention_mask: torch.Tensor | None = None,
+        position_ids: torch.LongTensor | None = None,
+        past_key_values: Cache | None = None,
+        cache_position: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> torch.FloatTensor:
+        residual = hidden_states
+
+        hidden_states = self.input_layernorm(hidden_states)
+
+        # Token Mixer
+        if self.layer_type == "linear_attention":
+            hidden_states = self.linear_attn(
+                hidden_states=hidden_states,
+                cache_params=past_key_values,
+                cache_position=cache_position,
+                attention_mask=attention_mask,
+            )
+        elif self.layer_type == "full_attention":
+            # Flash Attention requires 2D position_ids [batch, seq_len].
+            # Qwen3.5 mrope generates 4D [4, batch, seq_len] — extract the text dimension (index 0).
+            fa_position_ids = position_ids
+            if position_ids is not None and position_ids.ndim == 3:
+                fa_position_ids = position_ids[0]  # shape: [batch, seq_len]
+            # Self Attention
+            hidden_states, _ = self.self_attn(
+                hidden_states=hidden_states,
+                attention_mask=attention_mask,
+                position_ids=fa_position_ids,
+                past_key_values=past_key_values,
+                cache_position=cache_position,
+                position_embeddings=position_embeddings,
+                **kwargs,
+            )
+
+        hidden_states = residual + hidden_states
+
+        # Fully Connected
+        residual = hidden_states
+        hidden_states = self.post_attention_layernorm(hidden_states)
+        hidden_states = self.mlp(hidden_states)
+        hidden_states = residual + hidden_states
+
+        return hidden_states
+
+
+class QuasarPreTrainedModel(PreTrainedModel):
+    def _set_state_dict_hook(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
+        """Ultra-robust hook to remap model.language_model -> model prefix mismatch."""
+        keys = list(state_dict.keys())
+        remapped_count = 0
+        for key in keys:
+            if "language_model." in key:
+                new_key = key.replace("language_model.", "").replace("..", ".")
+                if new_key != key and new_key not in state_dict:
+                    state_dict[new_key] = state_dict.pop(key)
+                    remapped_count += 1
+        
+        # Also handle model prefix if it's missing or duplicate
+        # Checkpoint: model.language_model...
+        # If we are loading QuasarForCausalLM, prefix is "" (root).
+        # Normal parameters are model.layers...
+        # Checkpoint has model.language_model.layers...
+        # So replacing language_model. with "" gives exactly model.layers...
+        
+        # print(f"  [Hook] Remapped {remapped_count} keys (prefix: '{prefix}')")
+
+    config: QuasarConfig
+    base_model_prefix = "model"
+    supports_gradient_checkpointing = True
+    _no_split_modules = ["QuasarDecoderLayer", "QuasarVisionBlock"]
+    _skip_keys_device_placement = "past_key_values"
+    _supports_flash_attn = True
+    _supports_sdpa = True
+    _keys_to_ignore_on_load_unexpected = [r"^mtp.*"]
+    _can_record_outputs = {
+        "hidden_states": QuasarDecoderLayer,
+        "attentions": QuasarAttention,
+    }
+    _is_stateful = True
+
+    @torch.no_grad()
+    def _init_weights(self, module):
+        super()._init_weights(module)
+        if isinstance(module, QuasarGatedDeltaNet):
+            init.ones_(module.dt_bias)
+            init.copy_(module.A_log, torch.empty_like(module.A_log).uniform_(0, 16).log_())
+        # We initialize with 0s to be 1 centered as the RMSNorm here does (1 + weight)
+        elif isinstance(module, QuasarRMSNorm):
+            init.zeros_(module.weight)
+        elif isinstance(module, QuasarVisionRotaryEmbedding):
+            inv_freq = 1.0 / (module.theta ** (torch.arange(0, module.dim, 2, dtype=torch.float) / module.dim))
+            init.copy_(module.inv_freq, inv_freq)
+
+
+class QuasarVisionMLP(nn.Module):
+    def __init__(self, config):
+        super().__init__()
+        self.hidden_size = config.hidden_size
+        self.intermediate_size = config.intermediate_size
+        self.linear_fc1 = nn.Linear(self.hidden_size, self.intermediate_size, bias=True)
+        self.linear_fc2 = nn.Linear(self.intermediate_size, self.hidden_size, bias=True)
+        self.act_fn = ACT2FN[config.hidden_act]
+
+    def forward(self, hidden_state):
+        return self.linear_fc2(self.act_fn(self.linear_fc1(hidden_state)))
+
+
+class QuasarVisionPatchEmbed(nn.Module):
+    def __init__(self, config) -> None:
+        super().__init__()
+        self.patch_size = config.patch_size
+        self.temporal_patch_size = config.temporal_patch_size
+        self.in_channels = config.in_channels
+        self.embed_dim = config.hidden_size
+
+        kernel_size = [self.temporal_patch_size, self.patch_size, self.patch_size]
+        self.proj = nn.Conv3d(self.in_channels, self.embed_dim, kernel_size=kernel_size, stride=kernel_size, bias=True)
+
+    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
+        target_dtype = self.proj.weight.dtype
+        hidden_states = hidden_states.view(
+            -1, self.in_channels, self.temporal_patch_size, self.patch_size, self.patch_size
+        )
+        hidden_states = self.proj(hidden_states.to(dtype=target_dtype)).view(-1, self.embed_dim)
+        return hidden_states
+
+
+class QuasarVisionPatchMerger(nn.Module):
+    def __init__(self, config: QuasarVisionConfig, use_postshuffle_norm=False) -> None:
+        super().__init__()
+        self.hidden_size = config.hidden_size * (config.spatial_merge_size**2)
+        self.use_postshuffle_norm = use_postshuffle_norm
+        self.norm = nn.LayerNorm(self.hidden_size if use_postshuffle_norm else config.hidden_size, eps=1e-6)
+        self.linear_fc1 = nn.Linear(self.hidden_size, self.hidden_size)
+        self.act_fn = nn.GELU()
+        self.linear_fc2 = nn.Linear(self.hidden_size, config.out_hidden_size)
+
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        x = self.norm(x.view(-1, self.hidden_size) if self.use_postshuffle_norm else x).view(-1, self.hidden_size)
+        x = self.linear_fc2(self.act_fn(self.linear_fc1(x)))
+        return x
+
+
+def apply_rotary_pos_emb_vision(
+    q: torch.Tensor, k: torch.Tensor, cos: torch.Tensor, sin: torch.Tensor
+) -> tuple[torch.Tensor, torch.Tensor]:
+    orig_q_dtype = q.dtype
+    orig_k_dtype = k.dtype
+    q, k = q.float(), k.float()
+    cos, sin = cos.unsqueeze(-2).float(), sin.unsqueeze(-2).float()
+    q_embed = (q * cos) + (rotate_half(q) * sin)
+    k_embed = (k * cos) + (rotate_half(k) * sin)
+    q_embed = q_embed.to(orig_q_dtype)
+    k_embed = k_embed.to(orig_k_dtype)
+    return q_embed, k_embed
+
+
+class QuasarVisionAttention(nn.Module):
+    def __init__(self, config: QuasarVisionConfig) -> None:
+        super().__init__()
+        self.dim = config.hidden_size
+        self.num_heads = config.num_heads
+        self.head_dim = self.dim // self.num_heads
+        self.num_key_value_groups = 1  # needed for eager attention
+        self.qkv = nn.Linear(self.dim, self.dim * 3, bias=True)
+        self.proj = nn.Linear(self.dim, self.dim)
+        self.scaling = self.head_dim**-0.5
+        self.config = config
+        self.attention_dropout = 0.0
+        self.is_causal = False
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        cu_seqlens: torch.Tensor,
+        rotary_pos_emb: torch.Tensor | None = None,
+        position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None,
+        **kwargs,
+    ) -> torch.Tensor:
+        seq_length = hidden_states.shape[0]
+        query_states, key_states, value_states = (
+            self.qkv(hidden_states).reshape(seq_length, 3, self.num_heads, -1).permute(1, 0, 2, 3).unbind(0)
+        )
+        cos, sin = position_embeddings
+        query_states, key_states = apply_rotary_pos_emb_vision(query_states, key_states, cos, sin)
+
+        query_states = query_states.transpose(0, 1).unsqueeze(0)
+        key_states = key_states.transpose(0, 1).unsqueeze(0)
+        value_states = value_states.transpose(0, 1).unsqueeze(0)
+
+        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
+            self.config._attn_implementation, eager_attention_forward
+        )
+
+        if is_flash_attention_requested(self.config):
+            # Flash Attention: Use cu_seqlens for variable length attention
+            max_seqlen = (cu_seqlens[1:] - cu_seqlens[:-1]).max()
+            attn_output, _ = attention_interface(
+                self,
+                query_states,
+                key_states,
+                value_states,
+                attention_mask=None,
+                scaling=self.scaling,
+                dropout=0.0 if not self.training else self.attention_dropout,
+                cu_seq_lens_q=cu_seqlens,
+                cu_seq_lens_k=cu_seqlens,
+                max_length_q=max_seqlen,
+                max_length_k=max_seqlen,
+                is_causal=False,
+                **kwargs,
+            )
+        else:
+            # Other implementations: Process each chunk separately
+            lengths = cu_seqlens[1:] - cu_seqlens[:-1]
+            splits = [
+                torch.split(tensor, lengths.tolist(), dim=2) for tensor in (query_states, key_states, value_states)
+            ]
+
+            attn_outputs = [
+                attention_interface(
+                    self,
+                    q,
+                    k,
+                    v,
+                    attention_mask=None,
+                    scaling=self.scaling,
+                    dropout=0.0 if not self.training else self.attention_dropout,
+                    is_causal=False,
+                    **kwargs,
+                )[0]
+                for q, k, v in zip(*splits)
+            ]
+            attn_output = torch.cat(attn_outputs, dim=1)
+
+        attn_output = attn_output.reshape(seq_length, -1).contiguous()
+        attn_output = self.proj(attn_output)
+        return attn_output
+
+
+class QuasarVisionBlock(GradientCheckpointingLayer):
+    def __init__(self, config, attn_implementation: str = "sdpa") -> None:
+        super().__init__()
+        self.norm1 = nn.LayerNorm(config.hidden_size, eps=1e-6)
+        self.norm2 = nn.LayerNorm(config.hidden_size, eps=1e-6)
+        self.attn = QuasarVisionAttention(config=config)
+        self.mlp = QuasarVisionMLP(config=config)
+
+    def forward(
+        self,
+        hidden_states: torch.Tensor,
+        cu_seqlens: torch.Tensor,
+        rotary_pos_emb: torch.Tensor | None = None,
+        position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None,
+        **kwargs,
+    ) -> torch.Tensor:
+        hidden_states = hidden_states + self.attn(
+            self.norm1(hidden_states),
+            cu_seqlens=cu_seqlens,
+            rotary_pos_emb=rotary_pos_emb,
+            position_embeddings=position_embeddings,
+            **kwargs,
+        )
+        hidden_states = hidden_states + self.mlp(self.norm2(hidden_states))
+        return hidden_states
+
+
+class QuasarVisionModel(QuasarPreTrainedModel):
+    config: QuasarVisionConfig
+    input_modalities = ("image", "video")
+    _no_split_modules = ["QuasarVisionBlock"]
+    _can_record_outputs = {
+        "hidden_states": QuasarVisionBlock,
+        "attentions": QuasarVisionAttention,
+    }
+
+    def __init__(self, config, *inputs, **kwargs) -> None:
+        super().__init__(config, *inputs, **kwargs)
+        self.spatial_merge_size = config.spatial_merge_size
+        self.patch_size = config.patch_size
+        self.spatial_merge_unit = self.spatial_merge_size * self.spatial_merge_size
+
+        self.patch_embed = QuasarVisionPatchEmbed(
+            config=config,
+        )
+
+        self.pos_embed = nn.Embedding(config.num_position_embeddings, config.hidden_size)
+        self.num_grid_per_side = int(config.num_position_embeddings**0.5)
+
+        head_dim = config.hidden_size // config.num_heads
+        self.rotary_pos_emb = QuasarVisionRotaryEmbedding(head_dim // 2)
+
+        self.blocks = nn.ModuleList([QuasarVisionBlock(config) for _ in range(config.depth)])
+        self.merger = QuasarVisionPatchMerger(
+            config=config,
+            use_postshuffle_norm=False,
+        )
+
+        self.gradient_checkpointing = False
+
+        self.post_init()
+
+    def rot_pos_emb(self, grid_thw: torch.Tensor) -> torch.Tensor:
+        merge_size = self.spatial_merge_size
+        grid_thw_list = grid_thw.tolist()
+
+        max_hw = max(max(h, w) for _, h, w in grid_thw_list)
+        freq_table = self.rotary_pos_emb(max_hw)  # (max_hw, dim // 2)
+        device = freq_table.device
+
+        total_tokens = sum(t * h * w for t, h, w in grid_thw_list)
+        pos_ids = torch.empty((total_tokens, 2), dtype=torch.long, device=device)
+
+        offset = 0
+        for num_frames, height, width in grid_thw_list:
+            merged_h, merged_w = height // merge_size, width // merge_size
+
+            block_rows = torch.arange(merged_h, device=device)  # block row indices
+            block_cols = torch.arange(merged_w, device=device)  # block col indices
+            intra_row = torch.arange(merge_size, device=device)  # intra-block row offsets
+            intra_col = torch.arange(merge_size, device=device)  # intra-block col offsets
+
+            # Compute full-resolution positions
+            row_idx = block_rows[:, None, None, None] * merge_size + intra_row[None, None, :, None]
+            col_idx = block_cols[None, :, None, None] * merge_size + intra_col[None, None, None, :]
+
+            row_idx = row_idx.expand(merged_h, merged_w, merge_size, merge_size).reshape(-1)
+            col_idx = col_idx.expand(merged_h, merged_w, merge_size, merge_size).reshape(-1)
+
+            coords = torch.stack((row_idx, col_idx), dim=-1)
+
+            if num_frames > 1:
+                coords = coords.repeat(num_frames, 1)
+
+            num_tokens = coords.shape[0]
+            pos_ids[offset : offset + num_tokens] = coords
+            offset += num_tokens
+
+        embeddings = freq_table[pos_ids]  # lookup rotary embeddings
+        embeddings = embeddings.flatten(1)
+        return embeddings
+
+    def fast_pos_embed_interpolate(self, grid_thw):
+        grid_thw_list = grid_thw.tolist()
+        grid_ts = [row[0] for row in grid_thw_list]
+        grid_hs = [row[1] for row in grid_thw_list]
+        grid_ws = [row[2] for row in grid_thw_list]
+        device = self.pos_embed.weight.device
+
+        idx_list = [[] for _ in range(4)]
+        weight_list = [[] for _ in range(4)]
+
+        for t, h, w in grid_thw_list:
+            h_idxs = torch.linspace(0, self.num_grid_per_side - 1, h)
+            w_idxs = torch.linspace(0, self.num_grid_per_side - 1, w)
+
+            h_idxs_floor = h_idxs.int()
+            w_idxs_floor = w_idxs.int()
+            h_idxs_ceil = (h_idxs.int() + 1).clip(max=self.num_grid_per_side - 1)
+            w_idxs_ceil = (w_idxs.int() + 1).clip(max=self.num_grid_per_side - 1)
+
+            dh = h_idxs - h_idxs_floor
+            dw = w_idxs - w_idxs_floor
+
+            base_h = h_idxs_floor * self.num_grid_per_side
+            base_h_ceil = h_idxs_ceil * self.num_grid_per_side
+
+            indices = [
+                (base_h[None].T + w_idxs_floor[None]).flatten(),
+                (base_h[None].T + w_idxs_ceil[None]).flatten(),
+                (base_h_ceil[None].T + w_idxs_floor[None]).flatten(),
+                (base_h_ceil[None].T + w_idxs_ceil[None]).flatten(),
+            ]
+
+            weights = [
+                ((1 - dh)[None].T * (1 - dw)[None]).flatten(),
+                ((1 - dh)[None].T * dw[None]).flatten(),
+                (dh[None].T * (1 - dw)[None]).flatten(),
+                (dh[None].T * dw[None]).flatten(),
+            ]
+
+            for i in range(4):
+                idx_list[i].extend(indices[i].tolist())
+                weight_list[i].extend(weights[i].tolist())
+
+        idx_tensor = torch.tensor(idx_list, dtype=torch.long, device=device)
+        weight_tensor = torch.tensor(weight_list, dtype=self.pos_embed.weight.dtype, device=device)
+        pos_embeds = self.pos_embed(idx_tensor).to(device) * weight_tensor[:, :, None]
+        patch_pos_embeds = pos_embeds[0] + pos_embeds[1] + pos_embeds[2] + pos_embeds[3]
+
+        patch_pos_embeds = patch_pos_embeds.split([h * w for h, w in zip(grid_hs, grid_ws)])
+
+        patch_pos_embeds_permute = []
+        merge_size = self.config.spatial_merge_size
+        for pos_embed, t, h, w in zip(patch_pos_embeds, grid_ts, grid_hs, grid_ws):
+            pos_embed = pos_embed.repeat(t, 1)
+            pos_embed = (
+                pos_embed.view(t, h // merge_size, merge_size, w // merge_size, merge_size, -1)
+                .permute(0, 1, 3, 2, 4, 5)
+                .flatten(0, 4)
+            )
+            patch_pos_embeds_permute.append(pos_embed)
+        patch_pos_embeds = torch.cat(patch_pos_embeds_permute)
+        return patch_pos_embeds
+
+    @merge_with_config_defaults
+    @capture_outputs
+    def forward(self, hidden_states: torch.Tensor, grid_thw: torch.Tensor, **kwargs) -> torch.Tensor:
+        """
+        Args:
+            hidden_states (`torch.Tensor` of shape `(seq_len, hidden_size)`):
+                The final hidden states of the model.
+            grid_thw (`torch.Tensor` of shape `(num_images_or_videos, 3)`):
+                The temporal, height and width of feature shape of each image in LLM.
+
+        Returns:
+            `torch.Tensor`: hidden_states.
+        """
+        hidden_states = self.patch_embed(hidden_states)
+
+        pos_embeds = self.fast_pos_embed_interpolate(grid_thw)
+        hidden_states = hidden_states + pos_embeds
+
+        rotary_pos_emb = self.rot_pos_emb(grid_thw)
+
+        seq_len, _ = hidden_states.size()
+        hidden_states = hidden_states.reshape(seq_len, -1)
+        rotary_pos_emb = rotary_pos_emb.reshape(seq_len, -1)
+        emb = torch.cat((rotary_pos_emb, rotary_pos_emb), dim=-1)
+        position_embeddings = (emb.cos(), emb.sin())
+
+        cu_seqlens = torch.repeat_interleave(grid_thw[:, 1] * grid_thw[:, 2], grid_thw[:, 0]).cumsum(
+            dim=0,
+            # Select dtype based on the following factors:
+            #  - FA2 requires that cu_seqlens_q must have dtype int32
+            #  - torch.onnx.export requires that cu_seqlens_q must have same dtype as grid_thw
+            # See https://github.com/huggingface/transformers/pull/34852 for more information
+            dtype=grid_thw.dtype if torch.jit.is_tracing() else torch.int32,
+        )
+        cu_seqlens = F.pad(cu_seqlens, (1, 0), value=0)
+
+        for blk in self.blocks:
+            hidden_states = blk(
+                hidden_states,
+                cu_seqlens=cu_seqlens,
+                position_embeddings=position_embeddings,
+                **kwargs,
+            )
+
+        merged_hidden_states = self.merger(hidden_states)
+
+        return BaseModelOutputWithPooling(
+            last_hidden_state=hidden_states,
+            pooler_output=merged_hidden_states,
+        )
+
+
+@dataclass
+@auto_docstring(
+    custom_intro="""
+    Base class for Llava outputs, with hidden states and attentions.
+    """
+)
+class QuasarModelOutputWithPast(ModelOutput):
+    r"""
+    past_key_values (`Cache`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
+        It is a [`~cache_utils.Cache`] instance. For more details, see our [kv cache guide](https://huggingface.co/docs/transformers/en/kv_cache).
+
+        Contains pre-computed hidden-states (key and values in the self-attention blocks) that can be used (see
+        `past_key_values` input) to speed up sequential decoding.
+    rope_deltas (`torch.LongTensor` of shape `(batch_size, )`, *optional*):
+        The rope index difference between sequence length and multimodal rope.
+    """
+
+    last_hidden_state: torch.FloatTensor | None = None
+    past_key_values: Cache | None = None
+    hidden_states: tuple[torch.FloatTensor] | None = None
+    attentions: tuple[torch.FloatTensor] | None = None
+    rope_deltas: torch.LongTensor | None = None
+
+
+class QuasarTextModel(QuasarPreTrainedModel):
+    def __init__(self, config: QuasarTextConfig):
+        if hasattr(config, 'text_config'): config = config.text_config
+        if hasattr(config, 'text_config'): config = config.text_config
+        if hasattr(config, 'text_config'): config = config.text_config
+        # Handle cases where the multimodal wrapper is passed instead of the text config
+        if hasattr(config, "text_config"):
+            config = config.text_config
+        super().__init__(config)
+        self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, config.pad_token_id)
+        self.layers = nn.ModuleList(
+            [QuasarDecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)]
+        )
+        self.norm = QuasarRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
+        self.rotary_emb = QuasarTextRotaryEmbedding(config=config)
+        self.gradient_checkpointing = False
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    @merge_with_config_defaults
+    @capture_outputs
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: torch.LongTensor | None = None,
+        attention_mask: torch.Tensor | None = None,
+        position_ids: torch.LongTensor | None = None,
+        past_key_values: Cache | None = None,
+        inputs_embeds: torch.FloatTensor | None = None,
+        use_cache: bool | None = None,
+        cache_position: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> BaseModelOutputWithPast:
+        if (input_ids is None) ^ (inputs_embeds is not None):
+            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")
+
+        if inputs_embeds is None:
+            inputs_embeds = self.embed_tokens(input_ids)
+
+        if use_cache and past_key_values is None:
+            past_key_values = QuasarDynamicCache(config=self.config)
+
+        if cache_position is None:
+            past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0
+            cache_position = torch.arange(
+                past_seen_tokens, past_seen_tokens + inputs_embeds.shape[1], device=inputs_embeds.device
+            )
+
+        # mrope: the hard coded `4` is for text, temporal, height and width.
+        if position_ids is None:
+            position_ids = cache_position.view(1, 1, -1).expand(4, inputs_embeds.shape[0], -1)
+        elif position_ids.ndim == 2:
+            position_ids = position_ids[None, ...].expand(4, position_ids.shape[0], -1)
+
+        if position_ids.ndim == 3 and position_ids.shape[0] == 4:
+            text_position_ids = position_ids[0]
+            position_ids = position_ids[1:]
+        else:
+            text_position_ids = None
+
+        causal_mask = create_causal_mask(
+            config=self.config,
+            inputs_embeds=inputs_embeds,
+            attention_mask=attention_mask,
+            cache_position=cache_position,
+            past_key_values=past_key_values,
+            position_ids=text_position_ids,
+        )
+        linear_attn_mask = self._update_linear_attn_mask(attention_mask, cache_position)
+
+        all_hidden_states = () if kwargs.get("output_hidden_states", False) else None
+        hidden_states = inputs_embeds
+        position_embeddings = self.rotary_emb(hidden_states, position_ids)
+
+        for layer_idx, decoder_layer in enumerate(self.layers[: self.config.num_hidden_layers]):
+            if all_hidden_states is not None:
+                all_hidden_states += (hidden_states,)
+
+            layer_mask = linear_attn_mask if decoder_layer.layer_type == "linear_attention" else causal_mask
+
+            hidden_states = decoder_layer(
+                hidden_states,
+                position_embeddings=position_embeddings,
+                attention_mask=layer_mask,
+                position_ids=position_ids,
+                past_key_values=past_key_values,
+                use_cache=use_cache,
+                cache_position=cache_position,
+                **kwargs,
+            )
+
+        hidden_states = self.norm(hidden_states)
+        if all_hidden_states is not None:
+            all_hidden_states += (hidden_states,)
+
+        return QuasarModelOutputWithPast(
+            last_hidden_state=hidden_states,
+            past_key_values=past_key_values,
+            hidden_states=all_hidden_states,
+        )
+
+    def _update_linear_attn_mask(self, attention_mask, cache_position):
+        """
+        NOTE: Left-padding is used for linear attention mask.
+        No need for zeroing states when
+            1. Cached forward
+            2. Attending to all inputs
+        """
+        linear_attn_mask = attention_mask
+        if cache_position[0] > 0 or (attention_mask is not None and torch.all(attention_mask == 1)):
+            linear_attn_mask = None
+        return linear_attn_mask
+
+
+@auto_docstring
+class QuasarModel(QuasarPreTrainedModel):
+    base_model_prefix = "model"
+    _checkpoint_conversion_mapping = {}
+    # Reference: fix gemma3 grad acc #37208
+    accepts_loss_kwargs = False
+    config: QuasarConfig
+    _no_split_modules = ["QuasarDecoderLayer", "QuasarVisionBlock"]
+
+    def __init__(self, config):
+        super().__init__(config)
+        self.visual = QuasarVisionModel._from_config(config.vision_config)
+        self.language_model = QuasarTextModel._from_config(config.text_config)
+        self.rope_deltas = None  # cache rope_deltas here
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.language_model.get_input_embeddings()
+
+    def set_input_embeddings(self, value):
+        self.language_model.set_input_embeddings(value)
+
+    def get_vision_position_ids(
+        self,
+        start_position: int,
+        grid_thw: list[int, int, int] | torch.Tensor,
+        temp_merge_size: int = 1,
+        spatial_merge_size: int = 1,
+        time_interval: int = 1,
+        device: str | torch.device | None = None,
+    ):
+        """
+        Compute 3D positional indices for vision tokens derived from a single image or video input.
+
+        The positions are generated from the input grid defined by temporal (T), height (H), and
+        width (W) dimensions. Temporal and spatial dimensions can be downscaled according to the
+        merge sizes used in the vision backbone. The resulting positions are offset by `start_position`.
+
+        Args:
+            start_position (`int`):
+                Offset added to all computed positional indices.
+            grid_thw (`Sequence[int]` or `torch.Tensor` of shape `(3,)`):
+                The (T, H, W) grid representing the feature layout of the current image or video after patch embedding.
+            temp_merge_size (`int`, *optional*):
+                Factor by which the temporal dimension is reduced in the backbone. The temporal grid size is divided
+                by this value. Defaults to 1.
+            spatial_merge_size (`int`, *optional*):
+                Factor by which the spatial dimensions (H and W) are reduced in the backbone. Both H and W are divided
+                by this value. Defaults to 1.
+            time_interval (`int`, *optional*):
+                Spacing factor applied between consecutive temporal position indices.Defaults to 1.
+            device (`str` or `torch.device`, *optional*):
+                Device on which the resulting tensor is allocated. If `None`, uses the current default device.
+
+        Returns:
+            torch.LongTensor of shape (3, sequence_length):
+                Positional indices for temporal, height, and width dimensions,
+                flattened into sequence form and offset by `start_position`.
+        """
+        llm_grid_t, llm_grid_h, llm_grid_w = (
+            grid_thw[0].item() // temp_merge_size,
+            grid_thw[1].item() // spatial_merge_size,
+            grid_thw[2].item() // spatial_merge_size,
+        )
+
+        image_seq_length = llm_grid_h * llm_grid_w * llm_grid_t
+        position_width = torch.arange(start_position, start_position + llm_grid_w, device=device).repeat(
+            llm_grid_h * llm_grid_t
+        )
+        position_height = torch.arange(start_position, start_position + llm_grid_h, device=device).repeat_interleave(
+            llm_grid_w * llm_grid_t
+        )
+        position_temporal = torch.full((image_seq_length,), start_position, device=device, dtype=torch.long)
+        position_temporal = position_temporal * time_interval
+        vision_position_ids = torch.stack([position_temporal, position_height, position_width], dim=0)
+
+        return vision_position_ids
+
+    def get_rope_index(
+        self,
+        input_ids: torch.LongTensor,
+        mm_token_type_ids: torch.IntTensor,
+        image_grid_thw: torch.LongTensor | None = None,
+        video_grid_thw: torch.LongTensor | None = None,
+        attention_mask: torch.Tensor | None = None,
+        **kwargs,
+    ) -> tuple[torch.Tensor, torch.Tensor]:
+        """
+        Calculate the 3D rope index based on image and video's sizes. The utility expects a `vision + text`
+        sequence and will error out otherwise. For pure text sequence, please rely on model's auto-inferred
+        position ids. In a mixed vision + text sequence, vision tokens use 3D RoPE (temporal, height, width)
+        while text tokens use standard 1D RoPE.
+
+        Example:
+            Temporal patches: 3; Height patches: 2; Width patches: 2
+            Each vision input results in (temporal x height × width) positions. Here: 3 x 2 × 2 = 12 positions total.
+
+            Temporal position IDs are spaced by:
+                `interval = tokens_per_second * temporal_patch_size / fps`
+
+                If fps = 1; tokens_per_second = 25; temporal_patch_size = 2, temporal IDs increase by 50 for each temporal patch:
+                `[0, 0, 0, 0, 50, 50, 50, 50, 100, 100, 100, 100]`
+
+            Height IDs repeat per row: `[0, 0, 1, 1, ...]`
+            Width IDs alternate per column: `[0, 1, 0, 1, ...]`
+            Text tokens follow standard 1D RoPE and the position IDs grow consequently with a step of `1`
+
+        Args:
+            input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
+                Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide
+                it.
+            mm_token_type_ids (`torch.IntTensor` of shape `(batch_size, sequence_length)`):
+                Token type ids matching each modality to a different value in the input sequence, i.e. text (0), image (1), video (2).
+            image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
+                The temporal, height and width of feature shape of each image in LLM.
+            video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
+                The temporal, height and width of feature shape of each video in LLM.
+            attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*):
+                Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
+
+                - 1 for tokens that are **not masked**,
+                - 0 for tokens that are **masked**.
+
+        Returns:
+            position_ids (`torch.LongTensor` of shape `(3, batch_size, sequence_length)`)
+            mrope_position_deltas (`torch.Tensor` of shape `(batch_size)`)
+        """
+        spatial_merge_size = self.config.vision_config.spatial_merge_size
+
+        mrope_position_deltas = []
+        position_ids = torch.zeros(
+            3,
+            input_ids.shape[0],
+            input_ids.shape[1],
+            dtype=input_ids.dtype,
+            device=input_ids.device,
+        )
+        grid_iters = {
+            1: iter(image_grid_thw) if image_grid_thw is not None else None,
+            2: iter(video_grid_thw) if video_grid_thw is not None else None,
+        }
+
+        for batch_idx, current_input_ids in enumerate(input_ids):
+            input_token_type = mm_token_type_ids[batch_idx]
+            if attention_mask is not None:
+                current_input_ids = current_input_ids[attention_mask[batch_idx].bool()]
+                input_token_type = input_token_type[attention_mask[batch_idx].bool()]
+
+            input_type_group = []
+            for key, group in itertools.groupby(enumerate(input_token_type.tolist()), lambda x: x[1]):
+                group = list(group)
+                start_index = group[0][0]
+                end_index = group[-1][0] + 1
+                input_type_group.append((key, start_index, end_index))
+
+            current_pos = 0
+            llm_pos_ids_list = []
+            for modality_type, start_idx, end_idx in input_type_group:
+                # text == 0
+                if modality_type == 0:
+                    text_len = end_idx - start_idx
+                    llm_pos_ids_list.append(
+                        torch.arange(text_len, device=input_ids.device).view(1, -1).expand(3, -1) + current_pos
+                    )
+                    current_pos += text_len
+                # image == 1, video == 2
+                else:
+                    grid_thw = next(grid_iters[modality_type])
+                    vision_position_ids = self.get_vision_position_ids(
+                        current_pos, grid_thw, 1, spatial_merge_size, device=input_ids.device
+                    )
+                    llm_pos_ids_list.append(vision_position_ids)
+                    current_pos += max(grid_thw[1], grid_thw[2]) // spatial_merge_size
+            llm_positions = torch.cat(llm_pos_ids_list, dim=1).reshape(3, -1)
+            if attention_mask is not None:
+                position_ids[:, batch_idx, attention_mask[batch_idx].bool()] = llm_positions.to(position_ids.device)
+            else:
+                position_ids[:, batch_idx] = llm_positions.to(position_ids.device)
+            mrope_position_deltas.append(llm_positions.max() + 1 - len(current_input_ids))
+        mrope_position_deltas = torch.tensor(mrope_position_deltas, device=input_ids.device).unsqueeze(1)
+        return position_ids, mrope_position_deltas
+
+    @can_return_tuple
+    @auto_docstring
+    def get_video_features(
+        self,
+        pixel_values_videos: torch.FloatTensor,
+        video_grid_thw: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> tuple | BaseModelOutputWithPooling:
+        r"""
+        pixel_values_videos (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
+            The tensors corresponding to the input videos.
+        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
+            The temporal, height and width of feature shape of each video in LLM.
+        """
+        # Same implementation as for images
+        return self.get_image_features(pixel_values_videos, video_grid_thw, **kwargs)
+
+    @can_return_tuple
+    @auto_docstring
+    def get_image_features(
+        self,
+        pixel_values: torch.FloatTensor,
+        image_grid_thw: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> tuple | BaseModelOutputWithPooling:
+        r"""
+        pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
+            The tensors corresponding to the input images.
+        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
+            The temporal, height and width of feature shape of each image in LLM.
+        """
+        pixel_values = pixel_values.type(self.visual.dtype)
+        vision_output: BaseModelOutputWithPooling = self.visual(
+            pixel_values, grid_thw=image_grid_thw, return_dict=True, **kwargs
+        )
+        image_embeds = vision_output.pooler_output
+        split_sizes = (image_grid_thw.prod(-1) // self.visual.spatial_merge_size**2).tolist()
+        image_embeds = torch.split(image_embeds, split_sizes)
+        vision_output.pooler_output = image_embeds
+
+        return vision_output
+
+    def get_placeholder_mask(
+        self,
+        input_ids: torch.LongTensor,
+        inputs_embeds: torch.FloatTensor,
+        image_features: torch.FloatTensor | None = None,
+        video_features: torch.FloatTensor | None = None,
+    ):
+        """
+        Obtains multimodal placeholder mask from `input_ids` or `inputs_embeds`, and checks that the placeholder token count is
+        equal to the length of multimodal features. If the lengths are different, an error is raised.
+        """
+        if input_ids is None:
+            special_image_mask = inputs_embeds == self.get_input_embeddings()(
+                torch.tensor(self.config.image_token_id, dtype=torch.long, device=inputs_embeds.device)
+            )
+            special_image_mask = special_image_mask.all(-1)
+            special_video_mask = inputs_embeds == self.get_input_embeddings()(
+                torch.tensor(self.config.video_token_id, dtype=torch.long, device=inputs_embeds.device)
+            )
+            special_video_mask = special_video_mask.all(-1)
+        else:
+            special_image_mask = input_ids == self.config.image_token_id
+            special_video_mask = input_ids == self.config.video_token_id
+
+        n_image_tokens = special_image_mask.sum()
+        special_image_mask = special_image_mask.unsqueeze(-1).expand_as(inputs_embeds).to(inputs_embeds.device)
+        if image_features is not None:
+            torch_compilable_check(
+                inputs_embeds[special_image_mask].numel() == image_features.numel(),
+                f"Image features and image tokens do not match, tokens: {n_image_tokens}, features: {image_features.shape[0]}",
+            )
+
+        n_video_tokens = special_video_mask.sum()
+        special_video_mask = special_video_mask.unsqueeze(-1).expand_as(inputs_embeds).to(inputs_embeds.device)
+        if video_features is not None:
+            torch_compilable_check(
+                inputs_embeds[special_video_mask].numel() == video_features.numel(),
+                f"Video features and video tokens do not match, tokens: {n_video_tokens}, features: {video_features.shape[0]}",
+            )
+        return special_image_mask, special_video_mask
+
+    def compute_3d_position_ids(
+        self,
+        input_ids: torch.Tensor | None,
+        inputs_embeds: torch.Tensor | None,
+        image_grid_thw: torch.Tensor | None = None,
+        video_grid_thw: torch.Tensor | None = None,
+        attention_mask: torch.Tensor | None = None,
+        past_key_values: torch.Tensor | None = None,
+        mm_token_type_ids: torch.IntTensor | None = None,
+    ) -> torch.Tensor | None:
+        past_key_values_length = 0 if past_key_values is None else past_key_values.get_seq_length()
+        can_compute_mrope = (
+            input_ids is not None
+            and mm_token_type_ids is not None
+            and (image_grid_thw is not None or video_grid_thw is not None)
+        )
+
+        if can_compute_mrope and (self.rope_deltas is None or past_key_values_length == 0):
+            position_ids, rope_deltas = self.get_rope_index(
+                input_ids,
+                image_grid_thw=image_grid_thw,
+                video_grid_thw=video_grid_thw,
+                attention_mask=attention_mask,
+                mm_token_type_ids=mm_token_type_ids,
+            )
+            self.rope_deltas = rope_deltas
+        # Use pre-calculated rope-deltas to infer correct 3D position ids
+        elif self.rope_deltas is not None:
+            batch_size, seq_length, _ = inputs_embeds.shape
+            if attention_mask is not None:
+                position_ids = attention_mask.long().cumsum(-1) - 1
+                position_ids = position_ids.masked_fill(attention_mask == 0, 0)
+                position_ids = position_ids.view(1, batch_size, -1).repeat(3, 1, 1).to(inputs_embeds.device)
+            else:
+                position_ids = torch.arange(past_key_values_length, past_key_values_length + seq_length)
+                position_ids = position_ids.view(1, 1, -1).expand(3, batch_size, -1).to(inputs_embeds.device)
+            delta = self.rope_deltas.repeat_interleave(batch_size // self.rope_deltas.shape[0], dim=0)
+            position_ids = position_ids + delta.to(device=inputs_embeds.device)
+        else:
+            # Can't build correct 3D positions. Let the model infer it from `cache_position`
+            position_ids = None
+        return position_ids
+
+    @auto_docstring
+    @can_return_tuple
+    def forward(
+        self,
+        input_ids: torch.LongTensor = None,
+        attention_mask: torch.Tensor | None = None,
+        position_ids: torch.LongTensor | None = None,
+        past_key_values: Cache | None = None,
+        inputs_embeds: torch.FloatTensor | None = None,
+        pixel_values: torch.Tensor | None = None,
+        pixel_values_videos: torch.FloatTensor | None = None,
+        image_grid_thw: torch.LongTensor | None = None,
+        video_grid_thw: torch.LongTensor | None = None,
+        mm_token_type_ids: torch.IntTensor | None = None,
+        cache_position: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> tuple | QuasarModelOutputWithPast:
+        r"""
+        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
+            The temporal, height and width of feature shape of each image in LLM.
+        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
+            The temporal, height and width of feature shape of each video in LLM.
+        """
+        if (input_ids is None) ^ (inputs_embeds is not None):
+            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")
+
+        if inputs_embeds is None:
+            inputs_embeds = self.get_input_embeddings()(input_ids)
+
+        if pixel_values is not None:
+            image_outputs: BaseModelOutputWithPooling = self.get_image_features(
+                pixel_values, image_grid_thw, return_dict=True
+            )
+            image_embeds = image_outputs.pooler_output
+            image_embeds = torch.cat(image_embeds, dim=0).to(inputs_embeds.device, inputs_embeds.dtype)
+            image_mask, _ = self.get_placeholder_mask(
+                input_ids, inputs_embeds=inputs_embeds, image_features=image_embeds
+            )
+            inputs_embeds = inputs_embeds.masked_scatter(image_mask, image_embeds)
+
+        if pixel_values_videos is not None:
+            video_outputs: BaseModelOutputWithPooling = self.get_video_features(
+                pixel_values_videos, video_grid_thw, return_dict=True
+            )
+            video_embeds = video_outputs.pooler_output
+            video_embeds = torch.cat(video_embeds, dim=0).to(inputs_embeds.device, inputs_embeds.dtype)
+            _, video_mask = self.get_placeholder_mask(
+                input_ids, inputs_embeds=inputs_embeds, video_features=video_embeds
+            )
+            inputs_embeds = inputs_embeds.masked_scatter(video_mask, video_embeds)
+
+        if position_ids is None:
+            position_ids = self.compute_3d_position_ids(
+                input_ids=input_ids,
+                image_grid_thw=image_grid_thw,
+                video_grid_thw=video_grid_thw,
+                inputs_embeds=inputs_embeds,
+                attention_mask=attention_mask,
+                past_key_values=past_key_values,
+                mm_token_type_ids=mm_token_type_ids,
+            )
+
+        outputs = self.language_model(
+            input_ids=None,
+            position_ids=position_ids,
+            attention_mask=attention_mask,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            cache_position=cache_position,
+            **kwargs,
+        )
+
+        return QuasarModelOutputWithPast(
+            **outputs,
+            rope_deltas=self.rope_deltas,
+        )
+
+
+@auto_docstring
+class QuasarForCausalLM(QuasarPreTrainedModel, GenerationMixin):
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    _checkpoint_conversion_mapping = {
+        "model.language_model.layers": "model.layers",
+        "model.language_model.embed_tokens": "model.embed_tokens",
+        "model.language_model.norm": "model.norm",
+    }
+    _tied_weights_keys = {"lm_head.weight": "model.embed_tokens.weight"}
+    _tp_plan = {"lm_head": "colwise_gather_output"}
+    _pp_plan = {"lm_head": (["hidden_states"], ["logits"])}
+    config: QuasarTextConfig
+    _keys_to_ignore_on_load_unexpected = [r"^mtp.*", r"^model.visual.*"]
+
+    def __init__(self, config):
+        # Handle cases where the multimodal wrapper is passed instead of the text config
+        if hasattr(config, "text_config"):
+            config = config.text_config
+        super().__init__(config)
+        self.model = QuasarTextModel(config)
+        # Register the remapping hook directly on this instance
+        # Use a lambda to ensure the hook is called correctly as a pre-hook
+        self._register_load_state_dict_pre_hook(
+            lambda state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs: 
+            self._set_state_dict_hook(state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs)
+        )
+
+        self.vocab_size = config.vocab_size
+        self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
+
+        # Initialize weights and apply final processing
+        self.post_init()
+
+    @can_return_tuple
+    @auto_docstring
+    def forward(
+        self,
+        input_ids: torch.LongTensor | None = None,
+        attention_mask: torch.Tensor | None = None,
+        position_ids: torch.LongTensor | None = None,
+        past_key_values: Cache | None = None,
+        inputs_embeds: torch.FloatTensor | None = None,
+        labels: torch.LongTensor | None = None,
+        use_cache: bool | None = None,
+        cache_position: torch.LongTensor | None = None,
+        logits_to_keep: int | torch.Tensor = 0,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> CausalLMOutputWithPast:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
+            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
+            config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
+            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
+
+        Example:
+
+        ```python
+        >>> from transformers import AutoTokenizer, QuasarForCausalLM
+
+        >>> model = QuasarForCausalLM.from_pretrained("Qwen/Quasar-8B")
+        >>> tokenizer = AutoTokenizer.from_pretrained("Qwen/Quasar-8B")
+
+        >>> prompt = "Hey, are you conscious? Can you talk to me?"
+        >>> inputs = tokenizer(prompt, return_tensors="pt")
+
+        >>> # Generate
+        >>> generate_ids = model.generate(inputs.input_ids, max_length=30)
+        >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
+        "Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you."
+        ```"""
+        outputs: BaseModelOutputWithPast = self.model(
+            input_ids=input_ids,
+            attention_mask=attention_mask,
+            position_ids=position_ids,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            use_cache=use_cache,
+            cache_position=cache_position,
+            **kwargs,
+        )
+
+        hidden_states = outputs.last_hidden_state
+        # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
+        if isinstance(logits_to_keep, int) and logits_to_keep < 0:
+            logits = torch.empty((hidden_states.size(0), 0, self.config.vocab_size), device=hidden_states.device, dtype=hidden_states.dtype)
+        elif isinstance(logits_to_keep, int) and logits_to_keep == 0:
+            # 0 means return ALL logits for compatibility with eval harnesses like lm_eval
+            logits = self.lm_head(hidden_states)
+        else:
+            slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
+            logits = self.lm_head(hidden_states[:, slice_indices, :])
+
+        loss = None
+        if labels is not None:
+            loss = self.loss_function(logits=logits, labels=labels, vocab_size=self.config.vocab_size, **kwargs)
+
+        return CausalLMOutputWithPast(
+            loss=loss,
+            logits=logits,
+            past_key_values=outputs.past_key_values,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+        )
+
+
+@dataclass
+@auto_docstring(
+    custom_intro="""
+    Base class for Quasar causal language model (or autoregressive) outputs.
+    """
+)
+class QuasarCausalLMOutputWithPast(ModelOutput):
+    r"""
+    loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided):
+        Language modeling loss (for next-token prediction).
+    logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.vocab_size)`):
+        Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
+    past_key_values (`Cache`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
+        It is a [`~cache_utils.Cache`] instance. For more details, see our [kv cache guide](https://huggingface.co/docs/transformers/en/kv_cache).
+
+        Contains pre-computed hidden-states (key and values in the self-attention blocks) that can be used (see
+        `past_key_values` input) to speed up sequential decoding.
+    rope_deltas (`torch.LongTensor` of shape `(batch_size, )`, *optional*):
+        The rope index difference between sequence length and multimodal rope.
+    """
+
+    loss: torch.FloatTensor | None = None
+    logits: torch.FloatTensor | None = None
+    past_key_values: Cache | None = None
+    hidden_states: tuple[torch.FloatTensor] | None = None
+    attentions: tuple[torch.FloatTensor] | None = None
+    rope_deltas: torch.LongTensor | None = None
+
+
+class QuasarForConditionalGeneration(QuasarPreTrainedModel, GenerationMixin):
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    config_class = QuasarConfig
+    _checkpoint_conversion_mapping = {
+        "model.language_model.layers": "model.model.language_model.layers",
+        "model.language_model.embed_tokens": "model.model.language_model.embed_tokens",
+        "model.language_model.norm": "model.model.language_model.norm",
+        "model.visual": "model.visual",
+    }
+    _tied_weights_keys = {"lm_head.weight": "model.language_model.embed_tokens.weight"}
+    # Reference: fix gemma3 grad acc #37208
+    accepts_loss_kwargs = False
+    config: QuasarConfig
+
+    def __init__(self, config):
+        super().__init__(config)
+        self.model = QuasarModel(config)
+        self.lm_head = nn.Linear(config.text_config.hidden_size, config.text_config.vocab_size, bias=False)
+
+        self.post_init()
+
+    def get_input_embeddings(self):
+        return self.model.get_input_embeddings()
+
+    def set_input_embeddings(self, value):
+        self.model.set_input_embeddings(value)
+
+    @auto_docstring
+    def get_video_features(
+        self,
+        pixel_values_videos: torch.FloatTensor,
+        video_grid_thw: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> tuple | BaseModelOutputWithPooling:
+        r"""
+        pixel_values_videos (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
+            The tensors corresponding to the input videos.
+        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
+            The temporal, height and width of feature shape of each video in LLM.
+        """
+        return self.model.get_video_features(
+            pixel_values_videos=pixel_values_videos, video_grid_thw=video_grid_thw, **kwargs
+        )
+
+    @auto_docstring
+    def get_image_features(
+        self,
+        pixel_values: torch.FloatTensor,
+        image_grid_thw: torch.LongTensor | None = None,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> tuple | BaseModelOutputWithPooling:
+        r"""
+        pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
+            The tensors corresponding to the input images.
+        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
+            The temporal, height and width of feature shape of each image in LLM.
+        """
+        return self.model.get_image_features(pixel_values=pixel_values, image_grid_thw=image_grid_thw, **kwargs)
+
+    @can_return_tuple
+    def forward(
+        self,
+        input_ids: torch.LongTensor = None,
+        attention_mask: torch.Tensor | None = None,
+        position_ids: torch.LongTensor | None = None,
+        past_key_values: Cache | None = None,
+        inputs_embeds: torch.FloatTensor | None = None,
+        labels: torch.LongTensor | None = None,
+        pixel_values: torch.Tensor | None = None,
+        pixel_values_videos: torch.FloatTensor | None = None,
+        image_grid_thw: torch.LongTensor | None = None,
+        video_grid_thw: torch.LongTensor | None = None,
+        mm_token_type_ids: torch.IntTensor | None = None,
+        cache_position: torch.LongTensor | None = None,
+        logits_to_keep: int | torch.Tensor = 0,
+        **kwargs: Unpack[TransformersKwargs],
+    ) -> tuple | QuasarCausalLMOutputWithPast:
+        r"""
+        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
+            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
+            config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
+            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
+        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
+            The temporal, height and width of feature shape of each image in LLM.
+        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
+            The temporal, height and width of feature shape of each video in LLM.
+
+        Example:
+
+        ```python
+        >>> from transformers import AutoProcessor, QuasarForConditionalGeneration
+
+        >>> model = QuasarForConditionalGeneration.from_pretrained("Qwen/Qwen3-VL-8B-Instruct")
+        >>> processor = AutoProcessor.from_pretrained("Qwen/Qwen3-VL-8B-Instruct")
+
+        >>> messages = [
+            {
+                "role": "user",
+                "content": [
+                    {
+                        "type": "image",
+                        "image": "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/pipeline-cat-chonk.jpeg",
+                    },
+                    {"type": "text", "text": "Describe the image."},
+                ],
+            }
+        ]
+
+        >>> inputs = processor.apply_chat_template(
+            messages,
+            tokenize=True,
+            add_generation_prompt=True,
+            return_dict=True,
+            return_tensors="pt"
+        )
+
+        >>> # Generate
+        >>> generated_ids = model.generate(**inputs, max_new_tokens=1024)
+        >>> generated_ids_trimmed = [out_ids[len(in_ids) :] for in_ids, out_ids in zip(inputs.input_ids, generated_ids)]
+        >>> output_text = processor.batch_decode(generated_ids_trimmed, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
+        >>> print(output_text)
+        ```
+        """
+
+        outputs = self.model(
+            input_ids=input_ids,
+            pixel_values=pixel_values,
+            pixel_values_videos=pixel_values_videos,
+            image_grid_thw=image_grid_thw,
+            video_grid_thw=video_grid_thw,
+            position_ids=position_ids,
+            attention_mask=attention_mask,
+            past_key_values=past_key_values,
+            inputs_embeds=inputs_embeds,
+            cache_position=cache_position,
+            mm_token_type_ids=mm_token_type_ids,
+            **kwargs,
+        )
+
+        hidden_states = outputs[0]
+
+        # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
+        if isinstance(logits_to_keep, int) and logits_to_keep <= 0:
+            logits = None
+        else:
+            slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
+            logits = self.lm_head(hidden_states[:, slice_indices, :])
+
+        loss = None
+        if labels is not None:
+            loss = self.loss_function(logits=logits, labels=labels, vocab_size=self.config.text_config.vocab_size)
+
+        return QuasarCausalLMOutputWithPast(
+            loss=loss,
+            logits=logits,
+            past_key_values=outputs.past_key_values,
+            hidden_states=outputs.hidden_states,
+            attentions=outputs.attentions,
+            rope_deltas=outputs.rope_deltas,
+        )
+
+    def prepare_inputs_for_generation(
+        self,
+        input_ids,
+        past_key_values=None,
+        attention_mask=None,
+        inputs_embeds=None,
+        cache_position=None,
+        position_ids=None,
+        use_cache=True,
+        pixel_values=None,
+        pixel_values_videos=None,
+        image_grid_thw=None,
+        video_grid_thw=None,
+        is_first_iteration=False,
+        **kwargs,
+    ):
+        # Overwritten -- in specific circumstances we don't want to forward image inputs to the model
+
+        model_inputs = super().prepare_inputs_for_generation(
+            input_ids,
+            past_key_values=past_key_values,
+            attention_mask=attention_mask,
+            inputs_embeds=inputs_embeds,
+            cache_position=cache_position,
+            position_ids=position_ids,
+            pixel_values=pixel_values,
+            pixel_values_videos=pixel_values_videos,
+            image_grid_thw=image_grid_thw,
+            video_grid_thw=video_grid_thw,
+            use_cache=use_cache,
+            is_first_iteration=is_first_iteration,
+            **kwargs,
+        )
+
+        if not is_first_iteration and use_cache:
+            model_inputs["pixel_values"] = None
+            model_inputs["pixel_values_videos"] = None
+
+        return model_inputs
+
+    def _prepare_position_ids_for_generation(self, inputs_tensor, model_kwargs):
+        # Overwritten -- requires 3D position ids
+
+        text_positions = super()._prepare_position_ids_for_generation(inputs_tensor, model_kwargs)
+
+        # Early exit in case we are continuing generation from past kv
+        past_length = 0
+        if (cache := model_kwargs.get("past_key_values")) is not None:
+            past_length = cache.get_seq_length()
+        if past_length != 0 and self.model.rope_deltas is not None:
+            position_ids = text_positions[None, ...] + self.model.rope_deltas
+            return position_ids
+
+        # Otherwise compute 3d position ids for vision tokens and concat with text position ids
+        if "input_ids" in model_kwargs and model_kwargs["input_ids"].shape[1] > 0:
+            inputs_tensor = model_kwargs["input_ids"]
+
+        is_input_ids = len(inputs_tensor.shape) == 2 and inputs_tensor.dtype in [torch.int, torch.long]
+        if (
+            is_input_ids
+            and model_kwargs.get("mm_token_type_ids") is not None
+            and (model_kwargs.get("image_grid_thw") is not None or model_kwargs.get("video_grid_thw") is not None)
+        ):
+            model_kwargs = {k: v for k, v in model_kwargs.items() if k != "input_ids"}
+            vision_positions, rope_deltas = self.model.get_rope_index(inputs_tensor, **model_kwargs)
+            self.model.rope_deltas = rope_deltas
+        else:
+            vision_positions = text_positions.unsqueeze(0).expand(3, -1, -1)
+            self.model.rope_deltas = torch.zeros(
+                inputs_tensor.shape[0], 1, dtype=torch.long, device=inputs_tensor.device
+            )
+
+        # Concatenate "text + vision" positions into [4, bs, seq-len]
+        text_positions = text_positions[None, ...]
+        position_ids = torch.cat([text_positions, vision_positions], dim=0)
+
+        return position_ids
+
+    def _get_image_nums_and_video_nums(
+        self,
+        input_ids: torch.LongTensor | None,
+        inputs_embeds: torch.Tensor | None = None,
+    ) -> tuple[torch.Tensor, torch.Tensor]:
+        """
+        Get the number of images and videos for each sample to calculate the separation length of the sample tensor.
+        These parameters are not passed through the processor to avoid unpredictable impacts from interface modifications.
+
+        Args:
+            input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
+                Indices of input sequence tokens in the vocabulary.
+
+        Returns:
+            image_nums (`torch.LongTensor` of shape `(batch_size, num_images_sample)`)
+            video_nums (`torch.LongTensor` of shape `(batch_size, num_videos_sample)`)
+        """
+        image_token_id = self.config.image_token_id
+        video_token_id = self.config.video_token_id
+        vision_start_token_id = self.config.vision_start_token_id
+
+        if inputs_embeds is not None:
+            vision_start_mask = (
+                inputs_embeds
+                == self.get_input_embeddings()(
+                    torch.tensor(vision_start_token_id, dtype=torch.long, device=inputs_embeds.device)
+                )
+            )[..., 0]
+            image_mask = (
+                inputs_embeds
+                == self.get_input_embeddings()(
+                    torch.tensor(image_token_id, dtype=torch.long, device=inputs_embeds.device)
+                )
+            )[..., 0]
+            video_mask = (
+                inputs_embeds
+                == self.get_input_embeddings()(
+                    torch.tensor(video_token_id, dtype=torch.long, device=inputs_embeds.device)
+                )
+            )[..., 0]
+        else:
+            vision_start_mask = input_ids == vision_start_token_id
+            image_mask = input_ids == image_token_id
+            video_mask = input_ids == video_token_id
+
+        vision_first_mask = torch.roll(vision_start_mask, shifts=1, dims=1)
+        image_nums = torch.sum(vision_first_mask & image_mask, dim=1)
+        video_nums = torch.sum(vision_first_mask & video_mask, dim=1)
+
+        return image_nums, video_nums
+
+    def _expand_inputs_for_generation(
+        self,
+        expand_size: int = 1,
+        is_encoder_decoder: bool = False,
+        input_ids: torch.LongTensor | None = None,
+        **model_kwargs,
+    ) -> tuple[torch.LongTensor, dict[str, Any]]:
+        # Overwritten -- Quasar use timestamps and remove second_per_grid_ts
+        # Support for expanding tensors without a batch size dimension
+        # e.g., pixel_values, image_grid_thw, pixel_values_videos, video_grid_thw
+        # pixel_values.shape[0] is sum(seqlen_images for samples)
+        # image_grid_thw.shape[0] is sum(num_images for samples)
+
+        if expand_size == 1:
+            return input_ids, model_kwargs
+
+        visual_keys = ["pixel_values", "image_grid_thw", "pixel_values_videos", "video_grid_thw"]
+
+        def _expand_dict_for_generation_visual(dict_to_expand):
+            image_grid_thw = model_kwargs.get("image_grid_thw", None)
+            video_grid_thw = model_kwargs.get("video_grid_thw", None)
+            image_nums, video_nums = self._get_image_nums_and_video_nums(
+                input_ids, inputs_embeds=model_kwargs.get("inputs_embeds", None)
+            )
+
+            # video_nums: (batch_size,)
+            # since video_nums is the number of videos in the input dependent on the input_ids(vision_start),
+            # but Quasar append vision_start to each frame of each video, so we need to recover the real video_nums according to video_grid_thw
+            if video_grid_thw is not None:
+                cumulative_frame_counts = torch.cumsum(video_grid_thw[:, 0], dim=0)
+                cumulative_token_video_counts = torch.cumsum(video_nums, dim=0)
+                # Find video boundaries in cumulative_frame_counts
+                video_boundary_indices = torch.searchsorted(cumulative_frame_counts, cumulative_token_video_counts)
+                # example: video_boundary_indices = [3, 5] means video_nums = [4, 2]
+                video_nums = torch.diff(torch.cat([-video_boundary_indices.new_ones(1), video_boundary_indices]))
+
+            def _repeat_interleave_samples(x, lengths, repeat_times):
+                samples = torch.split(x, lengths)
+                repeat_args = [repeat_times] + [1] * (x.dim() - 1)
+                result = torch.cat([sample.repeat(*repeat_args) for sample in samples], dim=0)
+                return result
+
+            for key in dict_to_expand:
+                if key == "pixel_values":
+                    # split images into samples
+                    samples = torch.split(image_grid_thw, list(image_nums))
+                    # compute the sequence length of images for each sample
+                    lengths = [torch.prod(sample, dim=1).sum() for sample in samples]
+                    dict_to_expand[key] = _repeat_interleave_samples(
+                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
+                    )
+                elif key == "image_grid_thw":
+                    # get the num of images for each sample
+                    lengths = list(image_nums)
+                    dict_to_expand[key] = _repeat_interleave_samples(
+                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
+                    )
+                elif key == "pixel_values_videos":
+                    samples = torch.split(video_grid_thw, list(video_nums))
+                    lengths = [torch.prod(sample, dim=1).sum() for sample in samples]
+                    dict_to_expand[key] = _repeat_interleave_samples(
+                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
+                    )
+                elif key == "video_grid_thw":
+                    lengths = list(video_nums)
+                    dict_to_expand[key] = _repeat_interleave_samples(
+                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
+                    )
+            return dict_to_expand
+
+        def _expand_dict_for_generation(dict_to_expand):
+            for key in dict_to_expand:
+                if key == "position_ids" and dict_to_expand[key].ndim == 3:
+                    dict_to_expand[key] = dict_to_expand[key].repeat_interleave(expand_size, dim=1)
+                elif (
+                    key != "cache_position"
+                    and dict_to_expand[key] is not None
+                    and isinstance(dict_to_expand[key], torch.Tensor)
+                    and key not in visual_keys
+                ):
+                    dict_to_expand[key] = dict_to_expand[key].repeat_interleave(expand_size, dim=0)
+            return dict_to_expand
+
+        model_kwargs = _expand_dict_for_generation_visual(model_kwargs)
+
+        if input_ids is not None:
+            input_ids = input_ids.repeat_interleave(expand_size, dim=0)
+
+        model_kwargs = _expand_dict_for_generation(model_kwargs)
+
+        if is_encoder_decoder:
+            if model_kwargs.get("encoder_outputs") is None:
+                raise ValueError("If `is_encoder_decoder` is True, make sure that `encoder_outputs` is defined.")
+            model_kwargs["encoder_outputs"] = _expand_dict_for_generation(model_kwargs["encoder_outputs"])
+
+        return input_ids, model_kwargs
+
+
+__all__ = [
+    "QuasarVisionModel",
+    "QuasarTextModel",
+    "QuasarModel",
+    "QuasarForCausalLM",
+    "QuasarForConditionalGeneration",
+    "QuasarPreTrainedModel",
+]