drm/radeon: Clear surface registers at initialization time.

Some PowerMac firmwares set up a tiling surface at the beginning of VRAM
which messes us up otherwise.

Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 3f48a57531b5..f97563db4e59 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -35,6 +35,23 @@
 #include "atom.h"
 
 /*
+ * Clear GPU surface registers.
+ */
+static void radeon_surface_init(struct radeon_device *rdev)
+{
+        /* FIXME: check this out */
+        if (rdev->family < CHIP_R600) {
+                int i;
+
+                for (i = 0; i < 8; i++) {
+                        WREG32(RADEON_SURFACE0_INFO +
+                               i * (RADEON_SURFACE1_INFO - RADEON_SURFACE0_INFO),
+                               0);
+                }
+        }
+}
+
+/*
  * GPU scratch registers helpers function.
  */
 static void radeon_scratch_init(struct radeon_device *rdev)
@@ -496,6 +513,9 @@ int radeon_device_init(struct radeon_device *rdev,
         radeon_errata(rdev);
         /* Initialize scratch registers */
         radeon_scratch_init(rdev);
+        /* Initialize surface registers */
+        radeon_surface_init(rdev);
+
         /* TODO: disable VGA need to use VGA request */
         /* BIOS*/
         if (!radeon_get_bios(rdev)) {