linux-kernel - Re: [PATCH] drm/bridge: Fix lvds-encoder since the panel

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Message-ID: <1e94d083-b688-912e-1f11-533ada81408e@codeaurora.org>
Date:   Thu, 30 Nov 2017 12:17:13 +0530
From:   Archit Taneja <architt@...eaurora.org>
To:     Lothar Waßmann <LW@...O-electronics.de>,
        Eric Anholt <eric@...olt.net>
Cc:     dri-devel@...ts.freedesktop.org,
        Andrzej Hajda <a.hajda@...sung.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/bridge: Fix lvds-encoder since the panel_bridge
 rework.



On 11/15/2017 03:29 PM, Lothar Waßmann wrote:
> Hi,
> 
> On Tue, 14 Nov 2017 11:16:47 -0800 Eric Anholt wrote:
>> The panel_bridge bridge attaches to the panel's OF node, not the
>> lvds-encoder's node.  Put in a little no-op bridge of our own so that
>> our consumers can still find a bridge where they expect.
>>
>> This also fixes an unintended unregistration and leak of the
>> panel-bridge on module remove.
>>
>> Signed-off-by: Eric Anholt <eric@...olt.net>
>> Fixes: 13dfc0540a57 ("drm/bridge: Refactor out the panel wrapper from the lvds-encoder bri
>> dge.")
>> ---
>>
>> Note: I haven't actually tested this patch!  Hope it helps, though.
>>
>>   drivers/gpu/drm/bridge/lvds-encoder.c | 48 ++++++++++++++++++++++++++++++-----
>>   1 file changed, 41 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/lvds-encoder.c b/drivers/gpu/drm/bridge/lvds-encoder.c
>> index 0903ba574f61..75b0d3f6e4de 100644
>> --- a/drivers/gpu/drm/bridge/lvds-encoder.c
>> +++ b/drivers/gpu/drm/bridge/lvds-encoder.c
>> @@ -13,13 +13,37 @@
>>   
>>   #include <linux/of_graph.h>
>>   
>> +struct lvds_encoder {
>> +	struct drm_bridge bridge;
>> +	struct drm_bridge *panel_bridge;
>> +};
>> +
>> +static int lvds_encoder_attach(struct drm_bridge *bridge)
>> +{
>> +	struct lvds_encoder *lvds_encoder = container_of(bridge,
>> +							 struct lvds_encoder,
>> +							 bridge);
>> +
>> +	return drm_bridge_attach(bridge->encoder, lvds_encoder->panel_bridge,
>> +				 bridge);
>> +}
>> +
>> +static struct drm_bridge_funcs funcs = {
>> +	.attach = lvds_encoder_attach,
>> +};
>> +
>>   static int lvds_encoder_probe(struct platform_device *pdev)
>>   {
>>   	struct device_node *port;
>>   	struct device_node *endpoint;
>>   	struct device_node *panel_node;
>>   	struct drm_panel *panel;
>> -	struct drm_bridge *bridge;
>> +	struct lvds_encoder *lvds_encoder;
>> +
>> +	lvds_encoder = devm_kzalloc(&pdev->dev, sizeof(*lvds_encoder),
>> +				    GFP_KERNEL);
>> +	if (!lvds_encoder)
>> +		return -ENOMEM;
>>   
>>   	/* Locate the panel DT node. */
>>   	port = of_graph_get_port_by_id(pdev->dev.of_node, 1);
>> @@ -49,20 +73,30 @@ static int lvds_encoder_probe(struct platform_device *pdev)
>>   		return -EPROBE_DEFER;
>>   	}
>>   
>> -	bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_LVDS);
>> -	if (IS_ERR(bridge))
>> -		return PTR_ERR(bridge);
>> +	lvds_encoder->panel_bridge =
>> +		devm_drm_panel_bridge_add(&pdev->dev,
>> +					  panel, DRM_MODE_CONNECTOR_LVDS);
>> +	if (IS_ERR(lvds_encoder->panel_bridge))
>> +		return PTR_ERR(lvds_encoder->panel_bridge);
>> +
>> +	/* The panel_bridge bridge is attached to the panel's of_node,
>> +	 * but we need a bridge attached to our of_node for our user
>> +	 * to look up.
>> +	 */
>> +	lvds_encoder->bridge.of_node = pdev->dev.of_node;
>> +	lvds_encoder->bridge.funcs = &funcs;
>> +	drm_bridge_add(&lvds_encoder->bridge);
>>   
>> -	platform_set_drvdata(pdev, bridge);
>> +	platform_set_drvdata(pdev, lvds_encoder);
>>   
>>   	return 0;
>>   }
>>   
>>   static int lvds_encoder_remove(struct platform_device *pdev)
>>   {
>> -	struct drm_bridge *bridge = platform_get_drvdata(pdev);
>> +	struct lvds_encoder *lvds_encoder = platform_get_drvdata(pdev);
>>   
>> -	drm_bridge_remove(bridge);
>> +	drm_bridge_remove(&lvds_encoder->bridge);
>>   
>>   	return 0;
>>   }
>>
> Tested-by: Lothar Waßmann <LW@...O-electronics.de>

queued to drm-misc-fixes.

I think we should send this patch for the stable kernels (v4.12+) too.

Thanks,
Archit

> 
> 
> Lothar Waßmann
> 

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