linux-kernel - Re: [PATCH v2 09/10] drm/bridge: anx7625: update bridge

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Message-ID: <da9f80e6-bb4e-4568-aa2c-d70383b12e3a@quicinc.com>
Date: Wed, 12 Mar 2025 15:17:38 +0530
From: Ayushi Makhija <quic_amakhija@...cinc.com>
To: Dmitry Baryshkov <lumag@...nel.org>
CC: <linux-arm-msm@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <robdclark@...il.com>,
        <dmitry.baryshkov@...aro.org>, <sean@...rly.run>,
        <marijn.suijten@...ainline.org>, <andersson@...nel.org>,
        <robh@...nel.org>, <robh+dt@...nel.org>, <krzk+dt@...nel.org>,
        <konradybcio@...nel.org>, <conor+dt@...nel.org>,
        <andrzej.hajda@...el.com>, <neil.armstrong@...aro.org>,
        <rfoss@...nel.org>, <Laurent.pinchart@...asonboard.com>,
        <jonas@...boo.se>, <jernej.skrabec@...il.com>,
        <quic_abhinavk@...cinc.com>, <quic_rajeevny@...cinc.com>,
        <quic_vproddut@...cinc.com>, <quic_jesszhan@...cinc.com>
Subject: Re: [PATCH v2 09/10] drm/bridge: anx7625: update bridge_ops and sink
 detect logic

On 3/11/2025 9:11 PM, Dmitry Baryshkov wrote:
> On Tue, Mar 11, 2025 at 05:54:44PM +0530, Ayushi Makhija wrote:
>> The anx7625_link_bridge() checks if a device is not a panel
>> bridge and add DRM_BRIDGE_OP_HPD and DRM_BRIDGE_OP_DETECT to
>> the bridge operations. However, on port 1 of the anx7625
>> bridge, any device added is always treated as a panel
>> bridge, preventing connector_detect function from being
>> called. To resolve this, instead of just checking if it is a
>> panel bridge, verify the type of panel bridge
>> whether it is a DisplayPort or eDP panel. If the panel
>> bridge is not of the eDP type, add DRM_BRIDGE_OP_HPD and
>> DRM_BRIDGE_OP_DETECT to the bridge operations.
> 
> Are/were there any devices using anx7625, eDP panel _and_ not using the
> AUX bus? It would be better to use the precence of the 'aux' node to
> determine whether it is an eDP or a DP configuration.
> 
>>
>> In the anx7625_sink_detect(), the device is checked to see
>> if it is a panel bridge, and it always sends a "connected"
>> status to the connector. When adding the DP port on port 1 of the
>> anx7625, it incorrectly treats it as a panel bridge and sends an
>> always "connected" status. Instead of checking the status on the
>> panel bridge, it's better to check the hpd_status for connectors
>> like DisplayPort. This way, it verifies the hpd_status variable
>> before sending the status to the connector.
>>
>> Signed-off-by: Ayushi Makhija <quic_amakhija@...cinc.com>
>> ---
>>  drivers/gpu/drm/bridge/analogix/anx7625.c | 10 ++++------
>>  1 file changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
>> index 764da1c1dc11..ad99ad19653f 100644
>> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
>> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
>> @@ -1814,9 +1814,6 @@ static enum drm_connector_status anx7625_sink_detect(struct anx7625_data *ctx)
>>  
>>  	DRM_DEV_DEBUG_DRIVER(dev, "sink detect\n");
>>  
>> -	if (ctx->pdata.panel_bridge)
>> -		return connector_status_connected;
>> -
>>  	return ctx->hpd_status ? connector_status_connected :
>>  				     connector_status_disconnected;
>>  }
>> @@ -2608,9 +2605,10 @@ static int anx7625_link_bridge(struct drm_dp_aux *aux)
>>  	platform->bridge.of_node = dev->of_node;
>>  	if (!anx7625_of_panel_on_aux_bus(dev))
>>  		platform->bridge.ops |= DRM_BRIDGE_OP_EDID;
>> -	if (!platform->pdata.panel_bridge)
>> -		platform->bridge.ops |= DRM_BRIDGE_OP_HPD |
>> -					DRM_BRIDGE_OP_DETECT;
>> +	if (!platform->pdata.panel_bridge ||
>> +	    platform->pdata.panel_bridge->type != DRM_MODE_CONNECTOR_eDP) {
>> +		platform->bridge.ops |= DRM_BRIDGE_OP_HPD | DRM_BRIDGE_OP_DETECT;
>> +	}

Hi Dmitry,

Thanks, for the review.

Yes, it is better to check the presence of the 'aux' node for eDP or DP configuration.
Will change it in next patch.

-	if (!platform->pdata.panel_bridge)
-		platform->bridge.ops |= DRM_BRIDGE_OP_HPD |
-					DRM_BRIDGE_OP_DETECT;
+	if (!platform->pdata.panel_bridge || !anx7625_of_panel_on_aux_bus(dev)) {
+		platform->bridge.ops |= DRM_BRIDGE_OP_HPD | DRM_BRIDGE_OP_DETECT;
+	}

Thanks,
Ayushi