mxfp8 (for all gemm layouts) is not supported on 120+ arch yet (#1939)

* mxfp8 is not supported on 120+ arch yet
Signed-off-by: Sudhakar Singh <sudhakars@nvidia.com>

* change the default recipe for arch 120
Signed-off-by: Sudhakar Singh <sudhakars@nvidia.com>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci



---------
Signed-off-by: Sudhakar Singh <sudhakars@nvidia.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Tim Moon <4406448+timmoon10@users.noreply.github.com>

transformer_engine/pytorch/fp8.py

@@ -46,6 +46,8 @@ def check_fp8_support() -> Tuple[bool, str]:
 
 def check_mxfp8_support() -> Tuple[bool, str]:
     """Return if fp8 support is available"""
+    if get_device_compute_capability() >= (12, 0):
+        return False, "MXFP8 (for all gemm layouts) is not supported on 12.0+ architectures yet."
     if get_device_compute_capability() >= (10, 0):  # blackwell and above
         return True, ""
     return False, "Device compute capability 10.0 or higher required for MXFP8 execution."
@@ -64,7 +66,11 @@ def check_fp8_block_scaling_support() -> Tuple[bool, str]:
 
 def get_default_fp8_recipe() -> Recipe:
     """FP8 recipe with default args."""
-    if get_device_compute_capability() >= (10, 0):  # blackwell and above
+    if check_mxfp8_support()[0]:
+        # This is a temporary restriction until MXFP8 is supported for all
+        # gemm layouts.
+        if get_device_compute_capability() >= (12, 0):
+            return Float8BlockScaling()
         return MXFP8BlockScaling()
     return DelayedScaling()