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

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Message-ID: <CALT56yP+UDF1YeotceqOevr_NTeGjDVw92NwtPDgRK6GvvkyHw@mail.gmail.com>
Date: Wed, 12 Mar 2025 13:03:33 +0200
From: Dmitry Baryshkov <dbaryshkov@...il.com>
To: Ayushi Makhija <quic_amakhija@...cinc.com>
Cc: Dmitry Baryshkov <lumag@...nel.org>, 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 Wed, 12 Mar 2025 at 11:47, Ayushi Makhija <quic_amakhija@...cinc.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@...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)) {

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).


> +               platform->bridge.ops |= DRM_BRIDGE_OP_HPD | DRM_BRIDGE_OP_DETECT;
> +       }
>
> Thanks,
> Ayushi



-- 
With best wishes
Dmitry