[PATCH 2/3] drm/radeon: Always disable RADEON_GEM_GTT_UC along with RADEON_GEM_GTT_WC

Michel Dänzer michel at daenzer.net
Thu Nov 5 00:25:27 PST 2015


From: Michel Dänzer <michel.daenzer at amd.com>

Write-combining is a CPU feature. From the GPU POV, these both simply
mean no GPU<->CPU cache coherency.

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 drivers/gpu/drm/radeon/radeon_object.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index a35f5af..dda2ecf 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -231,7 +231,7 @@ int radeon_bo_create(struct radeon_device *rdev,
 	/* XXX: Write-combined CPU mappings of GTT seem broken on 32-bit
 	 * See https://bugs.freedesktop.org/show_bug.cgi?id=84627
 	 */
-	bo->flags &= ~RADEON_GEM_GTT_WC;
+	bo->flags &= ~(RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC);
 #elif defined(CONFIG_X86) && !defined(CONFIG_X86_PAT)
 	/* Don't try to enable write-combining when it can't work, or things
 	 * may be slow
@@ -243,7 +243,7 @@ int radeon_bo_create(struct radeon_device *rdev,
 
 	DRM_INFO_ONCE("Please enable CONFIG_MTRR and CONFIG_X86_PAT for "
 		      "better performance thanks to write-combining\n");
-	bo->flags &= ~RADEON_GEM_GTT_WC;
+	bo->flags &= ~(RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC);
 #endif
 
 	radeon_ttm_placement_from_domain(bo, domain);
-- 
2.6.2



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