drm/radeon: Disable uncacheable CPU mappings of GTT with RV6xx

They reportedly cause random GPU hangs.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91268

Reviewed-by: Christian König <christian.koenig@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index d302488..a35f5af 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -221,6 +221,12 @@ int radeon_bo_create(struct radeon_device *rdev,
        if (!(rdev->flags & RADEON_IS_PCIE))
                bo->flags &= ~(RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC);
 
+       /* Write-combined CPU mappings of GTT cause GPU hangs with RV6xx
+        * See https://bugs.freedesktop.org/show_bug.cgi?id=91268
+        */
+       if (rdev->family >= CHIP_RV610 && rdev->family <= CHIP_RV635)
+               bo->flags &= ~(RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC);
+
 #ifdef CONFIG_X86_32
        /* XXX: Write-combined CPU mappings of GTT seem broken on 32-bit
         * See https://bugs.freedesktop.org/show_bug.cgi?id=84627