linux-kernel - Re: [PATCH v2 2/9] drm/bridge: adv7511: handle unsupported InfoFrames

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Message-ID: <20251003-crystal-monkey-of-fantasy-ea4a1a@houat>
Date: Fri, 3 Oct 2025 15:06:04 +0200
From: Maxime Ripard <mripard@...nel.org>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
	Simona Vetter <simona@...ll.ch>, Liu Ying <victor.liu@....com>, 
	Andrzej Hajda <andrzej.hajda@...el.com>, Neil Armstrong <neil.armstrong@...aro.org>, 
	Robert Foss <rfoss@...nel.org>, Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
	Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
	Rob Clark <robin.clark@....qualcomm.com>, Dmitry Baryshkov <lumag@...nel.org>, 
	Abhinav Kumar <abhinav.kumar@...ux.dev>, Jessica Zhang <jessica.zhang@....qualcomm.com>, 
	Sean Paul <sean@...rly.run>, Marijn Suijten <marijn.suijten@...ainline.org>, 
	Sandy Huang <hjc@...k-chips.com>, Heiko Stübner <heiko@...ech.de>, 
	Andy Yan <andy.yan@...k-chips.com>, Samuel Holland <samuel@...lland.org>, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
	freedreno@...ts.freedesktop.org, linux-arm-kernel@...ts.infradead.org, 
	linux-rockchip@...ts.infradead.org, linux-sunxi@...ts.linux.dev
Subject: Re: [PATCH v2 2/9] drm/bridge: adv7511: handle unsupported InfoFrames

Hi,

On Sun, Sep 28, 2025 at 11:24:47AM +0300, Dmitry Baryshkov wrote:
> Make hdmi_write_hdmi_infoframe() and hdmi_clear_infoframe() callbacks
> return -EOPNOTSUPP for unsupported InfoFrames and make sure that
> atomic_check() callback doesn't allow unsupported InfoFrames to be
> enabled.
> 
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> ---
>  drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 20 ++++++++++++++++----
>  1 file changed, 16 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> index b9be8654130758e69ac7ccbc73a82cc25d731a5c..241f02143f59322a814b4b277082637d59be7d5f 100644
> --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
> @@ -906,8 +906,7 @@ static int adv7511_bridge_hdmi_clear_infoframe(struct drm_bridge *bridge,
>  		adv7511_packet_disable(adv7511, ADV7511_PACKET_ENABLE_SPARE1);
>  		break;
>  	default:
> -		drm_dbg_driver(adv7511->bridge.dev, "Unsupported HDMI InfoFrame %x\n", type);
> -		break;
> +		return -EOPNOTSUPP;
>  	}
>  
>  	return 0;
> @@ -966,19 +965,32 @@ static int adv7511_bridge_hdmi_write_infoframe(struct drm_bridge *bridge,
>  		adv7511_packet_enable(adv7511, ADV7511_PACKET_ENABLE_SPARE1);
>  		break;
>  	default:
> -		drm_dbg_driver(adv7511->bridge.dev, "Unsupported HDMI InfoFrame %x\n", type);
> -		break;
> +		return -EOPNOTSUPP;
>  	}

I'm completely fine with that part.

>  	return 0;
>  }
>  
> +static int adv7511_bridge_atomic_check(struct drm_bridge *bridge,
> +				       struct drm_bridge_state *bridge_state,
> +				       struct drm_crtc_state *crtc_state,
> +				       struct drm_connector_state *conn_state)
> +{
> +	/* should not happen, HDR support not enabled */
> +	if (drm_WARN_ON_ONCE(bridge->encoder->dev,
> +			     conn_state->hdmi.infoframes.hdr_drm.set))
> +		return -EOPNOTSUPP;
> +
> +	return 0;
> +}
> +

However, I'm not sure we need that boilerplate in any driver. I'd rather
expand the kunit test suite to make sure it never happens rather than
adding it to every driver.

Maxime

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