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>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d544de9..91b5f87 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7189,11 +7189,16 @@
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 @@
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 @@
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 @@
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;