[Intel-gfx] [PATCH] drm/i915/gtt: reduce overzealous alignment constraints for GGTT

Matthew Auld matthew.auld at intel.com
Thu Mar 3 10:02:29 UTC 2022


Currently this will enforce both 2M alignment and padding for any LMEM
pages inserted into the GGTT. However, this was only meant to be applied
to the compact-pt layout with the ppGTT. For the GGTT we can reduce the
alignment and padding to 64K.

Bspec: 45015
Fixes: 87bd701ee268 ("drm/i915: enforce min GTT alignment for discrete cards")
Signed-off-by: Matthew Auld <matthew.auld at intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Cc: Robert Beckett <bob.beckett at collabora.com>
Cc: Ramalingam C <ramalingam.c at intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gtt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
index 4bcdfcab3642..a5f5b2dda332 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
@@ -234,7 +234,8 @@ void i915_address_space_init(struct i915_address_space *vm, int subclass)
 	memset64(vm->min_alignment, I915_GTT_MIN_ALIGNMENT,
 		 ARRAY_SIZE(vm->min_alignment));
 
-	if (HAS_64K_PAGES(vm->i915) && NEEDS_COMPACT_PT(vm->i915)) {
+	if (HAS_64K_PAGES(vm->i915) && NEEDS_COMPACT_PT(vm->i915) &&
+	    subclass == VM_CLASS_PPGTT) {
 		vm->min_alignment[INTEL_MEMORY_LOCAL] = I915_GTT_PAGE_SIZE_2M;
 		vm->min_alignment[INTEL_MEMORY_STOLEN_LOCAL] = I915_GTT_PAGE_SIZE_2M;
 	} else if (HAS_64K_PAGES(vm->i915)) {
-- 
2.34.1



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