drm/amdgpu: extend xnack limit page fault timeout

Extending this timeout will prevent IH from storm interrupts coming
from SDMA while a page fault is active. Currently, on Aldebaran,
handling that many interrupts can take a lot of CPU time
(up to 4 seconds).
This eventually causes timeouts in other tasks.
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v4_0.c

@@ -1109,6 +1109,8 @@ static void sdma_v4_0_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
 		if (adev->asic_type == CHIP_ARCTURUS &&
 		    adev->sdma.instance[i].fw_version >= 14)
 			WREG32_SDMA(i, mmSDMA0_PUB_DUMMY_REG2, enable);
+		/* Extend page fault timeout to avoid interrupt storm */
+		WREG32_SDMA(i, mmSDMA0_UTCL1_TIMEOUT, 0x00800080);
 	}
 
 }