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Date:   Wed, 23 Jun 2021 05:16:08 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Kieran Bingham <kieran.bingham@ideasonboard.com>
Cc:     Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVERS FOR RENESAS" <dri-devel@lists.freedesktop.org>,
        "open list:DRM DRIVERS FOR RENESAS" 
        <linux-renesas-soc@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/3] drm: rcar-du: Only initialise TVM_TVSYNC mode when
 supported
Message-ID: <YNKZaCYOUqF3qUHL@pendragon.ideasonboard.com>
References: <20210622232024.3215248-1-kieran.bingham@ideasonboard.com>
 <20210622232024.3215248-3-kieran.bingham@ideasonboard.com>
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In-Reply-To: <20210622232024.3215248-3-kieran.bingham@ideasonboard.com>
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Hi Kieran,

Thank you for the patch.

On Wed, Jun 23, 2021 at 12:20:23AM +0100, Kieran Bingham wrote:
> From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> 
> The R-Car DU as found on the D3, E3, and V3U do not have support
> for an external synchronisation method.
> 
> In these cases, the dsysr cached register should not be initialised
> in DSYSR_TVM_TVSYNC, but instead should be left clear to configure as
> DSYSR_TVM_MASTER by default.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> index ea7e39d03545..cff0d82b9491 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
> @@ -1243,7 +1243,10 @@ int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int swindex,
>  	rcrtc->group = rgrp;
>  	rcrtc->mmio_offset = mmio_offsets[hwindex];
>  	rcrtc->index = hwindex;
> -	rcrtc->dsysr = (rcrtc->index % 2 ? 0 : DSYSR_DRES) | DSYSR_TVM_TVSYNC;
> +	rcrtc->dsysr = (rcrtc->index % 2 ? 0 : DSYSR_DRES);

You can drop the parentheses.

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

> +
> +	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_TVM_SYNC))
> +		rcrtc->dsysr |= DSYSR_TVM_TVSYNC;
>  
>  	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_VSP1_SOURCE))
>  		primary = &rcrtc->vsp->planes[rcrtc->vsp_pipe].plane;

-- 
Regards,

Laurent Pinchart