Re: [PATCH v2 09/10] drm/bridge: anx7625: update bridge_ops and sink detect logic

[Ayushi Makhija <quic_amakhija@quicinc.com>]

On 3/12/2025 4:33 PM, Dmitry Baryshkov wrote:
> On Wed, 12 Mar 2025 at 11:47, Ayushi Makhija <quic_amakhija@quicinc.com> wrote:
>>
>> 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@quicinc.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)) {
> 
> This is incorrect, if I'm not mistaken, please doublecheck it. I'd
> suggest following msm_dp_display_get_connector_type() (feel free to
> extract that to a helper function).
> 

Hi Dmirty,

Thanks, for the review.

If we see definition of anx7625_of_panel_on_aux_bus() it is doing the same
thing as msm_dp_display_get_connector_type().

static bool anx7625_of_panel_on_aux_bus(struct device *dev)
{
        struct device_node *bus, *panel;

        bus = of_get_child_by_name(dev->of_node, "aux-bus");

        // if aux-bus is not there it will return the false.
        if (!bus)
                return false;

        panel = of_get_child_by_name(bus, "panel");
        of_node_put(bus);

        // if panel is not there it will return the false.
        if (!panel)
                return false;
        of_node_put(panel);

        return true;
}

Above function will return true in case of eDP and false in case of DP.
So we can use anx7625_of_panel_on_aux_bus() to check whether it
is DP or eDP configuration based on aux.

I don't think so we need extract msm_dp_display_get_connector_type() to check the eDP or DP configuration based on aux.
Let me know, if I am missing anything.

Thanks,
Ayushi