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>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 9fcdc9a..0115b12 100644 (file)
--- 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)