Re: [PATCH 1/2] drm/mxsfb: Call drm_crtc_vblank_on/off

From: Stefan Agner <stefan@agner.ch>
To: Daniel Vetter <daniel@ffwll.ch>, laurent.pinchart@ideasonboard.com
Cc: Marek Vasut <marex@denx.de>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	DRI Development <dri-devel@lists.freedesktop.org>,
	NXP Linux Team <linux-imx@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Daniel Vetter <daniel.vetter@intel.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] drm/mxsfb: Call drm_crtc_vblank_on/off
Date: Thu, 28 May 2020 09:56:36 +0200	[thread overview]
Message-ID: <7911368105b92200b661f0fed39f5642@agner.ch> (raw)
In-Reply-To: <20200528054643.GQ206103@phenom.ffwll.local>

Hi Daniel,

On 2020-05-28 07:46, Daniel Vetter wrote:
> On Wed, May 27, 2020 at 11:47:56AM +0200, Daniel Vetter wrote:
>> mxsfb has vblank support, is atomic, but doesn't call
>> drm_crtc_vblank_on/off as it should. Not good.
>>
>> With my next patch to add the drm_crtc_vblank_reset to helpers this
>> means not even the very first crtc enabling will vblanks work anymore,
>> since they'll just stay off forever.
>>
>> Since mxsfb doesn't have any vblank waits of its own in the
>> enable/disable flow, nor an enable/disable_vblank callback we can do
>> the on/off as the first respectively last operation, and it should all
>> work.
>>
>> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
>> Cc: Marek Vasut <marex@denx.de>
>> Cc: Stefan Agner <stefan@agner.ch>
>> Cc: Shawn Guo <shawnguo@kernel.org>
>> Cc: Sascha Hauer <s.hauer@pengutronix.de>
>> Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
>> Cc: Fabio Estevam <festevam@gmail.com>
>> Cc: NXP Linux Team <linux-imx@nxp.com>
>> Cc: linux-arm-kernel@lists.infradead.org
> 
> Ping for some ack/review on this one here, it's holding up the subsystem
> wide fix in patch 2.

Sorry for the delay.

I guess that has the same effect as patch 14 in Laurent's patchset would
have:
https://lore.kernel.org/dri-devel/20200309195216.31042-15-laurent.pinchart@ideasonboard.com/

But should be rather trivial to rebase. So until Laurent's patchset is
ready, we can go with this fix.

Acked-by: Stefan Agner <stefan@agner.ch>

--
Stefan

> 
> Thanks, Daniel
> 
>> ---
>>  drivers/gpu/drm/mxsfb/mxsfb_drv.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
>> index 497cf443a9af..1891cd6deb2f 100644
>> --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
>> @@ -124,6 +124,7 @@ static void mxsfb_pipe_enable(struct drm_simple_display_pipe *pipe,
>>  	drm_panel_prepare(mxsfb->panel);
>>  	mxsfb_crtc_enable(mxsfb);
>>  	drm_panel_enable(mxsfb->panel);
>> +	drm_crtc_vblank_on(&pipe->crtc);
>>  }
>>
>>  static void mxsfb_pipe_disable(struct drm_simple_display_pipe *pipe)
>> @@ -133,6 +134,7 @@ static void mxsfb_pipe_disable(struct drm_simple_display_pipe *pipe)
>>  	struct drm_crtc *crtc = &pipe->crtc;
>>  	struct drm_pending_vblank_event *event;
>>
>> +	drm_crtc_vblank_off(&pipe->crtc);
>>  	drm_panel_disable(mxsfb->panel);
>>  	mxsfb_crtc_disable(mxsfb);
>>  	drm_panel_unprepare(mxsfb->panel);
>> --
>> 2.26.2
>>
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