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Subject: Re: [PATCH] drm:atmel: Enable the crtc vblank prior to crtc usage.
To:     Dan Sneddon <dan.sneddon@microchip.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        <dri-devel@lists.freedesktop.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
CC:     Boris Brezillon <bbrezillon@kernel.org>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Ludovic Desroches <ludovic.desroches@microchip.com>
References: <20210602160846.5013-1-dan.sneddon@microchip.com>
From:   Nicolas Ferre <nicolas.ferre@microchip.com>
Organization: microchip
Message-ID: <72ac51ca-a7df-c6ce-ba10-5dd26369e137@microchip.com>
Date:   Fri, 18 Jun 2021 10:05:11 +0200
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Hi Daniel, Sam,

On 02/06/2021 at 18:08, Dan Sneddon wrote:
> 'commit eec44d44a3d2 ("drm/atmel: Use drm_atomic_helper_commit")'
> removed the home-grown handling of atomic commits and exposed an issue
> in the crtc atomic commit handling where vblank is expected to be
> enabled but hasn't yet, causing kernel warnings during boot.  This patch
> cleans up the crtc vblank handling thus removing the warning on boot.
> 
> Fixes: eec44d44a3d2 ("drm/atmel: Use drm_atomic_helper_commit")
> 
> Signed-off-by: Dan Sneddon <dan.sneddon@microchip.com>

Is this fix need more input from us, is there something missing (aka ping)?

Regards,
   Nicolas


> ---
>   drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 17 ++++++++++-------
>   1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
> index 05ad75d155e8..cfe4fc69277e 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
> @@ -232,7 +232,6 @@ static void atmel_hlcdc_crtc_atomic_enable(struct drm_crtc *c,
>   
>   	pm_runtime_put_sync(dev->dev);
>   
> -	drm_crtc_vblank_on(c);
>   }
>   
>   #define ATMEL_HLCDC_RGB444_OUTPUT	BIT(0)
> @@ -343,8 +342,17 @@ static int atmel_hlcdc_crtc_atomic_check(struct drm_crtc *c,
>   
>   static void atmel_hlcdc_crtc_atomic_begin(struct drm_crtc *c,
>   					  struct drm_atomic_state *state)
> +{
> +	drm_crtc_vblank_on(c);
> +}
> +
> +static void atmel_hlcdc_crtc_atomic_flush(struct drm_crtc *c,
> +					  struct drm_atomic_state *state)
>   {
>   	struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&c->dev->event_lock, flags);
>   
>   	if (c->state->event) {
>   		c->state->event->pipe = drm_crtc_index(c);
> @@ -354,12 +362,7 @@ static void atmel_hlcdc_crtc_atomic_begin(struct drm_crtc *c,
>   		crtc->event = c->state->event;
>   		c->state->event = NULL;
>   	}
> -}
> -
> -static void atmel_hlcdc_crtc_atomic_flush(struct drm_crtc *crtc,
> -					  struct drm_atomic_state *state)
> -{
> -	/* TODO: write common plane control register if available */
> +	spin_unlock_irqrestore(&c->dev->event_lock, flags);
>   }
>   
>   static const struct drm_crtc_helper_funcs lcdc_crtc_helper_funcs = {
> 


-- 
Nicolas Ferre