drm/radeon: Don't read from CP ring write pointer registers.
Apparently this doesn't always work reliably, e.g. at resume time.
Just initialize to 0, so the ring is considered empty.
Tested with hibernation on Sumo and Cayman cards.
Should fix https://bugs.launchpad.net/ubuntu/+source/linux/+bug/820746/ .
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index f2204cb..11e44a3 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -990,7 +990,8 @@
/* Force read & write ptr to 0 */
WREG32(RADEON_CP_RB_CNTL, tmp | RADEON_RB_RPTR_WR_ENA | RADEON_RB_NO_UPDATE);
WREG32(RADEON_CP_RB_RPTR_WR, 0);
- WREG32(RADEON_CP_RB_WPTR, 0);
+ rdev->cp.wptr = 0;
+ WREG32(RADEON_CP_RB_WPTR, rdev->cp.wptr);
/* set the wb address whether it's enabled or not */
WREG32(R_00070C_CP_RB_RPTR_ADDR,
@@ -1007,9 +1008,6 @@
WREG32(RADEON_CP_RB_CNTL, tmp);
udelay(10);
rdev->cp.rptr = RREG32(RADEON_CP_RB_RPTR);
- rdev->cp.wptr = RREG32(RADEON_CP_RB_WPTR);
- /* protect against crazy HW on resume */
- rdev->cp.wptr &= rdev->cp.ptr_mask;
/* Set cp mode to bus mastering & enable cp*/
WREG32(RADEON_CP_CSQ_MODE,
REG_SET(RADEON_INDIRECT2_START, indirect2_start) |