Re: [PATCH v3 08/21] drm/bridge: tc358767: add get_edid bride operation

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>,
	Peter Senna Tschudin <peter.senna@gmail.com>,
	kbuild test robot <lkp@intel.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Neil Armstrong <narmstrong@baylibre.com>,
	dri-devel@lists.freedesktop.org,
	Andrzej Hajda <a.hajda@samsung.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Martyn Welch <martyn.welch@collabora.co.uk>
Subject: Re: [PATCH v3 08/21] drm/bridge: tc358767: add get_edid bride operation
Date: Sat, 11 Jul 2020 01:24:21 +0300	[thread overview]
Message-ID: <20200710222421.GL5964@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200703192417.372164-9-sam@ravnborg.org>

Hi Sam,

Thank you for the patch.

s/bride/bridge/ in the subject line.

On Fri, Jul 03, 2020 at 09:24:04PM +0200, Sam Ravnborg wrote:
> Prepare for chained bridge with the addition of
> get_edid support.
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Cc: Andrzej Hajda <a.hajda@samsung.com>
> Cc: Neil Armstrong <narmstrong@baylibre.com>
> Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
> Cc: Jonas Karlman <jonas@kwiboo.se>
> Cc: Jernej Skrabec <jernej.skrabec@siol.net>
> ---
>  drivers/gpu/drm/bridge/tc358767.c | 24 +++++++++++++++++-------
>  1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 85973ae728db..fb9d57967b2c 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -1317,6 +1317,20 @@ static void tc_bridge_mode_set(struct drm_bridge *bridge,
>  	tc->mode = *mode;
>  }
>  
> +static struct edid *tc_get_edid(struct drm_bridge *bridge,
> +				struct drm_connector *connector)
> +{
> +	struct tc_data *tc = bridge_to_tc(bridge);
> +	struct edid *edid;
> +
> +	edid = drm_get_edid(connector, &tc->aux.ddc);
> +
> +	kfree(tc->edid);
> +	tc->edid = edid;

The caller (drm_bridge_connector_get_modes_edid()) calls kfree(edid), so
if you want to store it internally, you'll have to make a copy. Can you
skip internal storage altogether by freeing the memory in
tc_connector_get_modes() ?

> +
> +	return edid;
> +}
> +
>  static int tc_connector_get_modes(struct drm_connector *connector)
>  {
>  	struct tc_data *tc = connector_to_tc(connector);
> @@ -1336,12 +1350,7 @@ static int tc_connector_get_modes(struct drm_connector *connector)
>  			return count;
>  	}
>  
> -	edid = drm_get_edid(connector, &tc->aux.ddc);
> -
> -	kfree(tc->edid);
> -	tc->edid = edid;
> -	if (!edid)
> -		return 0;
> +	edid = tc_get_edid(&tc->bridge, connector);
>  
>  	drm_connector_update_edid_property(connector, edid);
>  	count = drm_add_edid_modes(connector, edid);
> @@ -1452,6 +1461,7 @@ static const struct drm_bridge_funcs tc_bridge_funcs = {
>  	.disable = tc_bridge_disable,
>  	.mode_fixup = tc_bridge_mode_fixup,
>  	.detect = tc_bridge_detect,
> +	.get_edid = tc_get_edid,
>  };
>  
>  static bool tc_readable_reg(struct device *dev, unsigned int reg)
> @@ -1685,7 +1695,7 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  		return ret;
>  
>  	tc->bridge.funcs = &tc_bridge_funcs;
> -	tc->bridge.ops = DRM_BRIDGE_OP_DETECT;
> +	tc->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID;
>  
>  	tc->bridge.of_node = dev->of_node;
>  	drm_bridge_add(&tc->bridge);
> -- 
> 2.25.1
> 

-- 
Regards,

Laurent Pinchart
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