drm/i915: fix for when semaphore updates fail

This fixes a long standing issue where emitting the semaphore updates
may have failed, but we've already updated our internal data structure.

Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 9fcdc9a917eb..0115b12df573 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2001,10 +2001,12 @@ i915_gem_object_sync(struct drm_i915_gem_object *obj,
                 seqno = request->seqno;
         }
 
-        from->sync_seqno[idx] = seqno;
 
-        return to->sync_to(to, from, seqno - 1);
+        ret = to->sync_to(to, from, seqno - 1);
+        if (!ret)
+                from->sync_seqno[idx] = seqno;
 
+        return ret;
 }
 
 static void i915_gem_object_finish_gtt(struct drm_i915_gem_object *obj)