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Date:   Fri, 23 Jun 2023 17:59:33 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Geert Uytterhoeven <geert+renesas@glider.be>
Cc:     Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Magnus Damm <magnus.damm@gmail.com>,
        dri-devel@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 03/39] drm: renesas: shmobile: Fix overlay plane disable
Message-ID: <20230623145933.GG2112@pendragon.ideasonboard.com>
References: <cover.1687423204.git.geert+renesas@glider.be>
 <9feb39aaab796fc4b59c6c83c3d96757482f714d.1687423204.git.geert+renesas@glider.be>
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In-Reply-To: <9feb39aaab796fc4b59c6c83c3d96757482f714d.1687423204.git.geert+renesas@glider.be>
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Hi Geert,

Thank you for the patch.

On Thu, Jun 22, 2023 at 11:21:15AM +0200, Geert Uytterhoeven wrote:
> Merely writing zero to the CHn Source Image Format Register is not
> sufficient to disable a plane, as the programmed register value is not
> propagated immediately to the current side.  This can be seen when using
> the -P option of modetest: the extra plane is displayed correctly, but
> does not disappear after exit.
> 
> Fix this by doing the full update dance using the Blend Control
> Register, like is done when enabling the plane.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

> ---
>  drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c
> index 850986cee848226a..0e34573c3cb3d032 100644
> --- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c
> +++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c
> @@ -215,7 +215,10 @@ static int shmob_drm_plane_disable(struct drm_plane *plane,
>  
>  	splane->format = NULL;
>  
> +	lcdc_write(sdev, LDBCR, LDBCR_UPC(splane->index));
>  	lcdc_write(sdev, LDBnBSIFR(splane->index), 0);
> +	lcdc_write(sdev, LDBCR,
> +		   LDBCR_UPF(splane->index) | LDBCR_UPD(splane->index));
>  	return 0;
>  }
>  

-- 
Regards,

Laurent Pinchart