Merge tag 'drm-fixes-2021-03-19' of git://anongit.freedesktop.org/drm/drm

Pull drm fixes from Dave Airlie:
 "Regular fixes pull, pretty small set of fixes, a couple of i915 and
  amdgpu, one ttm, one nouveau and one omap. Probably smaller than usual
  for this time, so we'll see if something pops up next week or if this
  will continue to stay small.

  Summary:

  ttm:
   - Make ttm_bo_unpin() not wraparound on too many unpins

  omap:
   - Fix coccicheck warning in omap

  amdgpu:
   - DCN 3.0 gamma fixes
   - DCN 2.1 corrupt screen fix

  i915:
   - Workaround async flip + VT-d frame corruption on HSW/BDW
   - Fix NMI watchdog crash due to uninitialized OA buffer use on gen12+

  nouveau:
   - workaround oops with bo syncing"

* tag 'drm-fixes-2021-03-19' of git://anongit.freedesktop.org/drm/drm:
  nouveau: Skip unvailable ttm page entries
  drm/amd/display: Remove MPC gamut remap logic for DCN30
  drm/amd/display: Correct algorithm for reversed gamma
  drm/omap: dsi: fix unsigned expression compared with zero
  i915/perf: Start hrtimer only if sampling the OA buffer
  drm/i915: Workaround async flip + VT-d corruption on HSW/BDW
  drm/amd/display: Copy over soc values before bounding box creation
  drm/ttm: make ttm_bo_unpin more defensive

1 files changed, 4 insertions, 2 deletions

diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index e17be324d95f..b8ca13664fa2 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -612,9 +612,11 @@ static inline void ttm_bo_pin(struct ttm_buffer_object *bo)
 static inline void ttm_bo_unpin(struct ttm_buffer_object *bo)
 {
 	dma_resv_assert_held(bo->base.resv);
-	WARN_ON_ONCE(!bo->pin_count);
 	WARN_ON_ONCE(!kref_read(&bo->kref));
-	--bo->pin_count;
+	if (bo->pin_count)
+		--bo->pin_count;
+	else
+		WARN_ON_ONCE(true);
 }
 
 int ttm_mem_evict_first(struct ttm_bo_device *bdev,