Hello Ben Skeggs,
The patch 060810d7abaa: "drm/nouveau: fix locking issues in page flipping paths" from Jul 8, 2013, leads to the following Smatch warning: "drivers/gpu/drm/nouveau/nouveau_display.c:599 nouveau_crtc_page_flip() error: double unlock 'mutex:&chan->cli->mutex'"
drivers/gpu/drm/nouveau/nouveau_display.c 582 ret = nouveau_page_flip_emit(chan, old_bo, new_bo, s, &fence); 583 mutex_unlock(&chan->cli->mutex); ^^^^^^^^^^^^ Unlock.
584 if (ret) 585 goto fail_unreserve; 586 587 /* Update the crtc struct and cleanup */ 588 crtc->fb = fb; 589 590 ttm_eu_fence_buffer_objects(&ticket, &res, fence); 591 if (old_bo != new_bo) 592 nouveau_bo_unpin(old_bo); 593 nouveau_fence_unref(&fence); 594 return 0; 595 596 fail_unreserve: 597 ttm_eu_backoff_reservation(&ticket, &res); 598 fail_unpin: 599 mutex_unlock(&chan->cli->mutex); ^^^^^^^^^^^^ Second unlock.
600 if (old_bo != new_bo) 601 nouveau_bo_unpin(new_bo);
This looks simple enough to fix, but the previous two attempts at fixing the locking here have scared me a little. ;)
regards, dan carpenter