Merge tag 'drm-fixes-2021-12-10' of git://anongit.freedesktop.org/drm/drm

Pull drm fixes from Dave Airlie:
 "Regular fixes, pretty small overall, couple of core fixes, two i915
  and two amdgpu, hopefully it stays this quiet.

  ttm:
   - fix ttm_bo_swapout

  syncobj:
   - fix fence find bug with signalled fences

  i915:
   - fix error pointer deref in gem execbuffer
   - fix for GT init with GuC/HuC on ICL

  amdgpu:
   - DPIA fix
   - eDP fix"

* tag 'drm-fixes-2021-12-10' of git://anongit.freedesktop.org/drm/drm:
  drm/i915/gen11: Moving WAs to icl_gt_workarounds_init()
  drm/amd/display: prevent reading unitialized links
  drm/amd/display: Fix DPIA outbox timeout after S3/S4/reset
  drm/i915: Fix error pointer dereference in i915_gem_do_execbuffer()
  drm/syncobj: Deal with signalled fences in drm_syncobj_find_fence.
  drm/ttm: fix ttm_bo_swapout

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index c9a9d74f338c..c313a5b4549c 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -404,8 +404,17 @@ int drm_syncobj_find_fence(struct drm_file *file_private,
 
 	if (*fence) {
 		ret = dma_fence_chain_find_seqno(fence, point);
-		if (!ret)
+		if (!ret) {
+			/* If the requested seqno is already signaled
+			 * drm_syncobj_find_fence may return a NULL
+			 * fence. To make sure the recipient gets
+			 * signalled, use a new fence instead.
+			 */
+			if (!*fence)
+				*fence = dma_fence_get_stub();
+
 			goto out;
+		}
 		dma_fence_put(*fence);
 	} else {
 		ret = -EINVAL;