[PATCH 5.11 307/601] drm/tilcdc: send vblank event when disabling crtc

Greg Kroah-Hartman
2021-05-12T17:31:08Z

From: Quanyang Wang <quanyang.wang@windriver.com>

[ Upstream commit f1a75f4dd8edf272b6b7cdccf6ba6254ec9d15fa ]

When run xrandr to change resolution on Beaglebone Black board, it will
print the error information:

root@beaglebone:~# xrandr -display :0 --output HDMI-1 --mode 720x400
[drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
[drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:32:tilcdc crtc] commit wait timed out
[drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
[drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:34:HDMI-A-1] commit wait timed out
[drm:drm_crtc_commit_wait] *ERROR* flip_done timed out
[drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:31:plane-0] commit wait timed out
tilcdc 4830e000.lcdc: already pending page flip!

This is because there is operation sequence as below:

drm_atomic_connector_commit_dpms(mode is DRM_MODE_DPMS_OFF):
...
drm_atomic_helper_setup_commit <- init_completion(commit_A->flip_done)
drm_atomic_helper_commit_tail
tilcdc_crtc_atomic_disable
tilcdc_plane_atomic_update <- drm_crtc_send_vblank_event in tilcdc_crtc_irq
is skipped since tilcdc_crtc->enabled is 0
tilcdc_crtc_atomic_flush <- drm_crtc_send_vblank_event is skipped since
crtc->state->event is set to be NULL in
tilcdc_plane_atomic_update
drm_mode_setcrtc:
...
drm_atomic_helper_setup_commit <- init_completion(commit_B->flip_done)
drm_atomic_helper_wait_for_dependencies
drm_crtc_commit_wait <- wait for commit_A->flip_done completing

Just as shown above, the steps which could complete commit_A->flip_done
are all skipped and commit_A->flip_done will never be completed. This will
result a time-out ERROR when drm_crtc_commit_wait check the commit_A->flip_done.
So add drm_crtc_send_vblank_event in tilcdc_crtc_atomic_disable to
complete commit_A->flip_done.

Fixes: cb345decb4d2 ("drm/tilcdc: Use standard drm_atomic_helper_commit")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Reviewed-by: Jyri Sarha <jyri.sarha@iki.fi>
Tested-by: Jyri Sarha <jyri.sarha@iki.fi>
Signed-off-by: Jyri Sarha <jyri.sarha@iki.fi>
Link: https://patchwork.freedesktop.org/patch/msgid/20210209082415.382602-1-quanyang.wang@windriver.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index 30213708fc99..d99afd19ca08 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -515,6 +515,15 @@ static void tilcdc_crtc_off(struct drm_crtc *crtc, bool shutdown)

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);
+
tilcdc_crtc_disable_irqs(dev);

pm_runtime_put_sync(dev->dev);
--
2.30.2