drm/radeon/kms: add sanity check to wptr.

If we resume in a bad way, we'll get 0xffffffff in wptr, and then
oops with no console. This just adds a sanity check so that we can
avoid the oops and hopefully get more details out of people's systems.

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 138ddd4..c8f4b03 100644 (file)
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -744,6 +744,8 @@ int r100_cp_init(struct radeon_device *rdev, unsigned ring_size)
        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) |