1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index d3024883b844..84d45633d28c 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -221,11 +221,17 @@ 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
          */
-        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
@@ -235,9 +241,10 @@ int radeon_bo_create(struct radeon_device *rdev,
 #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;
+        if (bo->flags & RADEON_GEM_GTT_WC)
+                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 | RADEON_GEM_GTT_UC);
 #endif
 
         radeon_ttm_placement_from_domain(bo, domain);