2021-02-09 08:27:04

by quanyang wang

Subject: [RESEND][PATCH] drm/tilcdc: send vblank event when disabling crtc

From: Quanyang Wang <[email protected]>

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 <[email protected]>
---
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);
--
2.25.1

2021-02-10 01:20:32

by Jyri Sarha

Subject: Re: [RESEND][PATCH] drm/tilcdc: send vblank event when disabling crtc

On 2021-02-09 10:24, [email protected] wrote:
> From: Quanyang Wang <[email protected]>
>
> 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 <[email protected]>

Reviewed-by: Jyri Sarha <[email protected]>
Tested-by: Jyri Sarha <[email protected]>

Thanks a lot! I think I have bumbed into this once or twice, but latelu
I have had time to look into this. I'll merge this to drm-misc-next
soon.

Best regards,
Jyri

> ---
> 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);