linux-kernel - Re: [PATCH] drm/stm: ltdc: reset controller to avoid partial refresh

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Message-ID: <1487ab3d-60f6-4c85-d021-8dec7f1a99c2@st.com>
Date:   Fri, 5 Apr 2019 16:31:26 +0000
From:   Philippe CORNU <philippe.cornu@...com>
To:     Yannick FERTRE <yannick.fertre@...com>,
        Benjamin GAIGNARD <benjamin.gaignard@...com>,
        Vincent ABRIOU <vincent.abriou@...com>,
        "David Airlie" <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/stm: ltdc: reset controller to avoid partial refresh



On 4/3/19 11:24 AM, Yannick Fertré wrote:
> Display controller reset must be done as soon as possible after enable
> the clock to avoid partial refresh on screen.
> 
> Signed-off-by: Yannick Fertré <yannick.fertre@...com>
> ---
>   drivers/gpu/drm/stm/ltdc.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> index 32fd6a3..7bbe61c 100644
> --- a/drivers/gpu/drm/stm/ltdc.c
> +++ b/drivers/gpu/drm/stm/ltdc.c
> @@ -1134,6 +1134,12 @@ int ltdc_load(struct drm_device *ddev)
>   		return -ENODEV;
>   	}
>   
> +	if (!IS_ERR(rstc)) {
> +		reset_control_assert(rstc);
> +		usleep_range(10, 20);
> +		reset_control_deassert(rstc);
> +	}
> +
>   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	ldev->regs = devm_ioremap_resource(dev, res);
>   	if (IS_ERR(ldev->regs)) {
> @@ -1156,12 +1162,6 @@ int ltdc_load(struct drm_device *ddev)
>   		}
>   	}
>   
> -	if (!IS_ERR(rstc)) {
> -		reset_control_assert(rstc);
> -		usleep_range(10, 20);
> -		reset_control_deassert(rstc);
> -	}
> -

Dear Yannick,
Thank you for your patch,

Acked-by: Philippe Cornu <philippe.cornu@...com>

Philippe :)

>   	/* Disable interrupts */
>   	reg_clear(ldev->regs, LTDC_IER,
>   		  IER_LIE | IER_RRIE | IER_FUIE | IER_TERRIE);
>