drm/i915: don't set unpin_work if vblank_get fails

This fixes a race where we may try to finish a page flip and decrement
the refcount even if our vblank_get failed and we ended up with a
spurious flip pending interrupt.

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=34211.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Jesse Barnes 2011-08-29 09:45:28 -07:00 committed by Keith Packard
parent c0f372b374
commit 7317c75e66
1 changed files with 7 additions and 5 deletions

View File

@ -7189,11 +7189,16 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
work->old_fb_obj = intel_fb->obj;
INIT_WORK(&work->work, intel_unpin_work_fn);
ret = drm_vblank_get(dev, intel_crtc->pipe);
if (ret)
goto free_work;
/* We borrow the event spin lock for protecting unpin_work */
spin_lock_irqsave(&dev->event_lock, flags);
if (intel_crtc->unpin_work) {
spin_unlock_irqrestore(&dev->event_lock, flags);
kfree(work);
drm_vblank_put(dev, intel_crtc->pipe);
DRM_DEBUG_DRIVER("flip queue: crtc already busy\n");
return -EBUSY;
@ -7212,10 +7217,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
crtc->fb = fb;
ret = drm_vblank_get(dev, intel_crtc->pipe);
if (ret)
goto cleanup_objs;
work->pending_flip_obj = obj;
work->enable_stall_check = true;
@ -7238,7 +7239,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
cleanup_pending:
atomic_sub(1 << intel_crtc->plane, &work->old_fb_obj->pending_flip);
cleanup_objs:
drm_gem_object_unreference(&work->old_fb_obj->base);
drm_gem_object_unreference(&obj->base);
mutex_unlock(&dev->struct_mutex);
@ -7247,6 +7247,8 @@ cleanup_objs:
intel_crtc->unpin_work = NULL;
spin_unlock_irqrestore(&dev->event_lock, flags);
drm_vblank_put(dev, intel_crtc->pipe);
free_work:
kfree(work);
return ret;