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Date:   Tue, 09 Feb 2021 09:58:45 +0200
From:   Jyri Sarha <jyri.sarha@iki.fi>
To:     "quanyang.wang" <quanyang.wang@windriver.com>
Cc:     Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/tilcdc: send vblank event when disabling crtc
In-Reply-To: <40037f81-2444-1fe0-f5da-194f2a3d3f22@windriver.com>
References: <20210129055831.1702862-1-quanyang.wang@windriver.com>
 <1c6bd553-ee27-c93b-59e6-8d3c8368213a@ideasonboard.com>
 <40037f81-2444-1fe0-f5da-194f2a3d3f22@windriver.com>
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On 2021-02-09 5:09, quanyang.wang wrote:
> Ping.
> 

Could you resend the original patch (I have not received it) so I can 
easily test and merge it?

I'll find some time to do it soon.

Best regards,
Jyri

> On 1/29/21 3:58 PM, Tomi Valkeinen wrote:
>> Dropped the @ti.com addresses and added the new ones.
>> 
>>   Tomi
>> 
>> On 29/01/2021 07:58, quanyang.wang@windriver.com wrote:
>>> From: Quanyang Wang <quanyang.wang@windriver.com>
>>> 
>>> 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>
>>> ---
>>>   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);
>>>