From: Michel Dänzer <michel.daen...@amd.com> 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 at vger.kernel.org Signed-off-by: Michel Dänzer <michel.daenzer at amd.com> --- drivers/gpu/drm/radeon/radeon_object.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c index 7d68223..bd3df10 100644 --- a/drivers/gpu/drm/radeon/radeon_object.c +++ b/drivers/gpu/drm/radeon/radeon_object.c @@ -238,6 +238,18 @@ int radeon_bo_create(struct radeon_device *rdev, * See https://bugs.freedesktop.org/show_bug.cgi?id=84627 */ 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 radeon_ttm_placement_from_domain(bo, domain); -- 2.1.4
