add

comfy/ldm/modules/attention.py

@@ -45,7 +45,8 @@ try:
     AITER_ATTENTION_IS_AVAILABLE = True
 except ImportError:
     if model_management.aiter_attention_enabled():
-        logging.error(f"\n\nTo use the `--use-aiter-attention` feature, the `aiter` package must be installed first.\ncommand:\n\t{sys.executable} -m pip install aiter")
+        logging.error(f"\n\nTo use the `--use-aiter-attention` feature, the `aiter` package must be installed first.")
+        logging.error(f"Installation instructions: https://github.com/ROCm/aiter/tree/main?tab=readme-ov-file#installation")
         exit(-1)
 
 REGISTERED_ATTENTION_FUNCTIONS = {}
@@ -629,42 +630,46 @@ def attention_flash(q, k, v, heads, mask=None, attn_precision=None, skip_reshape
     return out
 
 
-def aiter_flash_attn_wrapper(q: torch.Tensor, k: torch.Tensor, v: torch.Tensor,
-                dropout_p: float = 0.0, softmax_scale: Optional[float] = None,
-                causal: bool = False, window_size: tuple = (-1, -1),
-                bias: Optional[torch.Tensor] = None, alibi_slopes: Optional[torch.Tensor] = None,
-                deterministic: bool = False) -> torch.Tensor:
-    """Wrapper for aiter.flash_attn_func to handle its specific parameters"""
-    return aiter.flash_attn_func(q, k, v, dropout_p=dropout_p, softmax_scale=softmax_scale,
-                                 causal=causal, window_size=window_size, bias=bias,
-                                 alibi_slopes=alibi_slopes, deterministic=deterministic,
-                                 return_lse=False, return_attn_probs=False,
-                                 cu_seqlens_q=None, cu_seqlens_kv=None)
-
 @wrap_attn
 def attention_aiter(q, k, v, heads, mask=None, attn_precision=None, skip_reshape=False, skip_output_reshape=False, **kwargs):
+    # Store original inputs for fallback
+    q_orig, k_orig, v_orig, mask_orig = q, k, v, mask
+    
     if skip_reshape:
         b, _, _, dim_head = q.shape
+        q, k, v = map(
+            lambda t: t.transpose(1, 2),
+            (q, k, v),
+        )
     else:
         b, _, dim_head = q.shape
         dim_head //= heads
-        # reshape to (batch, seqlen, nheads, headdim) for aiter
         q, k, v = map(
             lambda t: t.view(b, -1, heads, dim_head),
             (q, k, v),
         )
 
+    
+    # Convert mask to [sq, sk] format for aiter bias
+    bias = None
     if mask is not None:
-        # add a batch dimension if there isn't already one
         if mask.ndim == 2:
-            mask = mask.unsqueeze(0)
+            bias = mask
-        # add a heads dimension if there isn't already one
+        elif mask.ndim == 3:
-        if mask.ndim == 3:
+            seqlen_q = q.shape[1]
-            mask = mask.unsqueeze(1)
+            if mask.shape[-2] == 1:
+                # [1, 1, sk] -> expand to [sq, sk]
+                bias = mask.squeeze(0).expand(seqlen_q, -1)
+            else:
+                # [batch, sq, sk] -> take first batch
+                bias = mask[0]
+        elif mask.ndim == 4:
+            # [batch, heads, sq, sk] -> take first batch and head
+            bias = mask[0, 0]
 
     try:
         # aiter.flash_attn_func expects (batch, seqlen, nheads, headdim) format
-        out = aiter_flash_attn_wrapper(
+        out = aiter.flash_attn_func(
             q,
             k,
             v,
@@ -672,26 +677,29 @@ def attention_aiter(q, k, v, heads, mask=None, attn_precision=None, skip_reshape
             softmax_scale=None,
             causal=False,
             window_size=(-1, -1),
-            bias=mask,
+            bias=bias,
             alibi_slopes=None,
             deterministic=False,
+            return_lse=False,
+            return_attn_probs=False,
+            cu_seqlens_q=None,
+            cu_seqlens_kv=None,
         )
-    except Exception as e:
-        logging.warning(f"Aiter Attention failed, using default SDPA: {e}")
-        # fallback needs (batch, nheads, seqlen, headdim) format
-        q_sdpa = q.transpose(1, 2)
-        k_sdpa = k.transpose(1, 2)
-        v_sdpa = v.transpose(1, 2)
-        out = torch.nn.functional.scaled_dot_product_attention(q_sdpa, k_sdpa, v_sdpa, attn_mask=mask, dropout_p=0.0, is_causal=False)
-        out = out.transpose(1, 2)
         
-    if skip_output_reshape:
+        if skip_output_reshape:
-        # output is already in (batch, seqlen, nheads, headdim), need (batch, nheads, seqlen, headdim)
+            # output is (batch, seqlen, nheads, headdim), need (batch, nheads, seqlen, headdim)
-        out = out.transpose(1, 2)
+            out = out.transpose(1, 2)
-    else:
+        else:
-        # reshape from (batch, seqlen, nheads, headdim) to (batch, seqlen, nheads * headdim)
+            # reshape from (batch, seqlen, nheads, headdim) to (batch, seqlen, nheads * headdim)
-        out = out.reshape(b, -1, heads * dim_head)
+            out = out.reshape(b, -1, heads * dim_head)
-    return out
+        return out
+        
+    except Exception as e:
+        logging.warning(f"Aiter Attention failed, falling back to pytorch attention: {e}")
+        # Fallback to attention_pytorch with original inputs
+        return attention_pytorch(q_orig, k_orig, v_orig, heads, mask=mask_orig, 
+                                attn_precision=attn_precision, skip_reshape=skip_reshape, 
+                                skip_output_reshape=skip_output_reshape, **kwargs)
 
 
 optimized_attention = attention_basic
@@ -1170,5 +1178,3 @@ class SpatialVideoTransformer(SpatialTransformer):
             x = self.proj_out(x)
         out = x + x_in
         return out
-
-