Commit a53fa438 authored by Michel Dänzer's avatar Michel Dänzer Committed by Alex Deucher

drm/radeon: Don't try to enable write-combining without PAT

Doing so can cause things to become slow.

Print a warning at compile time and an informative message at runtime in
that case.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88758
Cc: stable@vger.kernel.org
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 082452e1
...@@ -238,6 +238,18 @@ int radeon_bo_create(struct radeon_device *rdev, ...@@ -238,6 +238,18 @@ int radeon_bo_create(struct radeon_device *rdev,
* See https://bugs.freedesktop.org/show_bug.cgi?id=84627 * See https://bugs.freedesktop.org/show_bug.cgi?id=84627
*/ */
bo->flags &= ~RADEON_GEM_GTT_WC; bo->flags &= ~RADEON_GEM_GTT_WC;
#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
* See https://bugs.freedesktop.org/show_bug.cgi?id=88758
*/
#warning Please enable CONFIG_MTRR and CONFIG_X86_PAT for better performance \
thanks to write-combining
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;
#endif #endif
radeon_ttm_placement_from_domain(bo, domain); radeon_ttm_placement_from_domain(bo, domain);
......
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