releases/3.1.10/drm-radeon-kms-disable-writeback-on-pre-r300-asics.patch

   1 From 28eebb703e28bc455ba704adb1026f76649b768c Mon Sep 17 00:00:00 2001
   2 From: Alex Deucher <alexander.deucher@amd.com>
   3 Date: Tue, 3 Jan 2012 09:48:38 -0500
   4 Subject: drm/radeon/kms: disable writeback on pre-R300 asics
   5
   6 From: Alex Deucher <alexander.deucher@amd.com>
   7
   8 commit 28eebb703e28bc455ba704adb1026f76649b768c upstream.
   9
  10 We often end up missing fences on older asics with
  11 writeback enabled which leads to delays in the userspace
  12 accel code, so just disable it by default on those asics.
  13
  14 Reported-by: Helge Deller <deller@gmx.de>
  15 Reported-by: Dave Airlie <airlied@redhat.com>
  16 Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
  17 Signed-off-by: Dave Airlie <airlied@redhat.com>
  18 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  19
  20 ---
  21  drivers/gpu/drm/radeon/radeon_device.c |    5 ++++-
  22  1 file changed, 4 insertions(+), 1 deletion(-)
  23
  24 --- a/drivers/gpu/drm/radeon/radeon_device.c
  25 +++ b/drivers/gpu/drm/radeon/radeon_device.c
  26 @@ -224,8 +224,11 @@ int radeon_wb_init(struct radeon_device
  27         if (radeon_no_wb == 1)
  28                 rdev->wb.enabled = false;
  29         else {
  30 -               /* often unreliable on AGP */
  31                 if (rdev->flags & RADEON_IS_AGP) {
  32 +                       /* often unreliable on AGP */
  33 +                       rdev->wb.enabled = false;
  34 +               } else if (rdev->family < CHIP_R300) {
  35 +                       /* often unreliable on pre-r300 */
  36                         rdev->wb.enabled = false;
  37                 } else {
  38                         rdev->wb.enabled = true;