[PATCH 4.19 58/90] drm/imx: notify drm core before sending event during crtc disable

Greg Kroah-Hartman
2019-07-08T15:39:53Z

From: Robert Beckett <bob.beckett@collabora.com>

commit 78c68e8f5cd24bd32ba4ca1cdfb0c30cf0642685 upstream.

Notify drm core before sending pending events during crtc disable.
This fixes the first event after disable having an old stale timestamp
by having drm_crtc_vblank_off update the timestamp to now.

This was seen while debugging weston log message:
Warning: computed repaint delay is insane: -8212 msec

This occurred due to:
1. driver starts up
2. fbcon comes along and restores fbdev, enabling vblank
3. vblank_disable_fn fires via timer disabling vblank, keeping vblank
seq number and time set at current value
(some time later)
4. weston starts and does a modeset
5. atomic commit disables crtc while it does the modeset
6. ipu_crtc_atomic_disable sends vblank with old seq number and time

Fixes: a474478642d5 ("drm/imx: fix crtc vblank state regression")

Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/imx/ipuv3-crtc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -98,14 +98,14 @@ static void ipu_crtc_atomic_disable(stru
ipu_dc_disable(ipu);
ipu_prg_disable(ipu);

+ drm_crtc_vblank_off(crtc);
+
spin_lock_irq(&crtc->dev->event_lock);
if (crtc->state->event) {
drm_crtc_send_vblank_event(crtc, crtc->state->event);
crtc->state->event = NULL;
}
spin_unlock_irq(&crtc->dev->event_lock);
-
- drm_crtc_vblank_off(crtc);
}

static void imx_drm_crtc_reset(struct drm_crtc *crtc)