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>

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index 3f48a57..f97563d 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -34,6 +34,23 @@
 #include "radeon_asic.h"
 #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.
  */
@@ -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)) {