Re: [PATCH v1 03/12] drm/mediatek: Drop chain_mode_fixup call in mode_valid()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sam,

Thank you for the patch.

On Sun, Jul 17, 2022 at 07:44:45PM +0200, Sam Ravnborg wrote:
> The mode_valid implementation had a call to
> drm_bridge_chain_mode_fixup() which would be wrong as the mode_valid is
> not allowed to change anything - only to validate the mode.
> 
> As the next bridge is often/always a connector the call had no effect
> anyway. So drop it.
> 
> From the git history I could see this call was included in the original
> version of the driver so there was no help there to find out why it was
> added in the first place. But a lot has changed since the initial driver
> were added and is seems safe to remove the call now.
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Reviewed-by: Maxime Ripard <mripard@kernel.org>
> Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org>
> Cc: Philipp Zabel <p.zabel@pengutronix.de>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> Cc: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> Cc: linux-mediatek@lists.infradead.org
> Cc: linux-arm-kernel@lists.infradead.org

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

> ---
>  drivers/gpu/drm/mediatek/mtk_hdmi.c | 11 -----------
>  1 file changed, 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> index 3196189429bc..a63b76055f81 100644
> --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> @@ -1208,22 +1208,11 @@ static int mtk_hdmi_bridge_mode_valid(struct drm_bridge *bridge,
>  				      const struct drm_display_mode *mode)
>  {
>  	struct mtk_hdmi *hdmi = hdmi_ctx_from_bridge(bridge);
> -	struct drm_bridge *next_bridge;
>  
>  	dev_dbg(hdmi->dev, "xres=%d, yres=%d, refresh=%d, intl=%d clock=%d\n",
>  		mode->hdisplay, mode->vdisplay, drm_mode_vrefresh(mode),
>  		!!(mode->flags & DRM_MODE_FLAG_INTERLACE), mode->clock * 1000);
>  
> -	next_bridge = drm_bridge_get_next_bridge(&hdmi->bridge);
> -	if (next_bridge) {
> -		struct drm_display_mode adjusted_mode;
> -
> -		drm_mode_copy(&adjusted_mode, mode);
> -		if (!drm_bridge_chain_mode_fixup(next_bridge, mode,
> -						 &adjusted_mode))
> -			return MODE_BAD;
> -	}
> -
>  	if (hdmi->conf) {
>  		if (hdmi->conf->cea_modes_only && !drm_match_cea_mode(mode))
>  			return MODE_BAD;

-- 
Regards,

Laurent Pinchart