This somehow fixes an issue where sync-to-vblank longer works correctly
after resume from suspend.
From a HW perspective, we don't need the IRQs turned on to be able to
detect flip completion, so it's assumed that this is required for the
voodoo in the core DRM vblank core.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
                }
        }
 
+       for_each_crtc_in_state(state, crtc, crtc_state, i) {
+               if (crtc->state->event)
+                       drm_crtc_vblank_get(crtc);
+       }
+
        /* Update plane(s). */
        for_each_plane_in_state(state, plane, plane_state, i) {
                struct nv50_wndw_atom *asyw = nv50_wndw_atom(plane->state);
                        drm_crtc_send_vblank_event(crtc, crtc->state->event);
                        spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
                        crtc->state->event = NULL;
+                       drm_crtc_vblank_put(crtc);
                }
        }