drm/vc4: Send a VBLANK event when disabling a CRTC

VBLANK events are missed when the CRTC is being disabled because the
driver does not wait till the end of the frame before stopping the
HVS and PV blocks. In this case, we should explicitly issue a VBLANK
event if there's one waiting.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: http://patchwork.freedesktop.org/patch/msgid/1497601833-24588-1-git-send-email-boris.brezillon@free-electrons.com

diff --git a/drivers/gpu/drm/vc4/vc4_crtc.c b/drivers/gpu/drm/vc4/vc4_crtc.c
index e3f03efe719b11987d8dc7f3d1ec1a2f508dbe72..30a1df11e0632b4a8435ddc1dffac8100d8a6ee5 100644 (file)
--- a/drivers/gpu/drm/vc4/vc4_crtc.c
+++ b/drivers/gpu/drm/vc4/vc4_crtc.c
@@ -518,6 +518,19 @@ static void vc4_crtc_disable(struct drm_crtc *crtc)
        WARN_ON_ONCE((HVS_READ(SCALER_DISPSTATX(chan)) &
                      (SCALER_DISPSTATX_FULL | SCALER_DISPSTATX_EMPTY)) !=
                     SCALER_DISPSTATX_EMPTY);
+
+       /*
+        * Make sure we issue a vblank event after disabling the CRTC if
+        * someone was waiting it.
+        */
+       if (crtc->state->event) {
+               unsigned long flags;
+
+               spin_lock_irqsave(&dev->event_lock, flags);
+               drm_crtc_send_vblank_event(crtc, crtc->state->event);
+               crtc->state->event = NULL;
+               spin_unlock_irqrestore(&dev->event_lock, flags);
+       }
 }
 
 static void vc4_crtc_enable(struct drm_crtc *crtc)