FIXME: It is suspected that some Address Translation Service (ATS) issue on IOMMU is causing CAT errors to occur on some MTL workloads. Applying a write barrier to the ppgtt set entry functions appeared to have no effect, so we must temporarily use I915_MAP_WC in the map_pt_dma class of functions on MTL until a proper ATS solution is found. Signed-off-by: Jonathan Cavitt <jonathan.cavitt@xxxxxxxxx> CC: Chris Wilson <chris.p.wilson@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/i915/gt/intel_gtt.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c index 4fbed27ef0ecc..21719563a602a 100644 --- a/drivers/gpu/drm/i915/gt/intel_gtt.c +++ b/drivers/gpu/drm/i915/gt/intel_gtt.c @@ -95,6 +95,16 @@ int map_pt_dma(struct i915_address_space *vm, struct drm_i915_gem_object *obj) void *vaddr; type = intel_gt_coherent_map_type(vm->gt, obj, true); + /* + * FIXME: It is suspected that some Address Translation Service (ATS) + * issue on IOMMU is causing CAT errors to occur on some MTL workloads. + * Applying a write barrier to the ppgtt set entry functions appeared + * to have no effect, so we must temporarily use I915_MAP_WC here on + * MTL until a proper ATS solution is found. + */ + if (IS_METEORLAKE(vm->i915)) + type = I915_MAP_WC; + vaddr = i915_gem_object_pin_map_unlocked(obj, type); if (IS_ERR(vaddr)) return PTR_ERR(vaddr); @@ -109,6 +119,16 @@ int map_pt_dma_locked(struct i915_address_space *vm, struct drm_i915_gem_object void *vaddr; type = intel_gt_coherent_map_type(vm->gt, obj, true); + /* + * FIXME: It is suspected that some Address Translation Service (ATS) + * issue on IOMMU is causing CAT errors to occur on some MTL workloads. + * Applying a write barrier to the ppgtt set entry functions appeared + * to have no effect, so we must temporarily use I915_MAP_WC here on + * MTL until a proper ATS solution is found. + */ + if (IS_METEORLAKE(vm->i915)) + type = I915_MAP_WC; + vaddr = i915_gem_object_pin_map(obj, type); if (IS_ERR(vaddr)) return PTR_ERR(vaddr); -- 2.25.1
