Re: [PATCH] drm/bridge: ite-it66121: Add drm_connector support

From: Dmitry Baryshkov

Date: Thu Sep 11 2025 - 09:09:30 EST


On Thu, Sep 11, 2025 at 02:49:59PM +0200, Miguel Gazquez wrote:
>
>
> Le 11/09/2025 à 11:50, Maxime Ripard a écrit :
> > On Thu, Sep 11, 2025 at 10:51:06AM +0200, Miguel Gazquez wrote:
> > >
> > >
> > > Le 10/09/2025 à 04:28, Dmitry Baryshkov a écrit :
> > > > On Tue, Sep 09, 2025 at 06:16:43PM +0200, Miguel Gazquez wrote:
> > > > > From: Aradhya Bhatia <a-bhatia1@xxxxxx>
> > > > >
> > > > > Add support for DRM connector and make the driver support the older
> > > > > format of attaching connectors onto the encoder->bridge->connector
> > > > > chain.
> > > > > This makes the driver compatible with display controller that only
> > > > > supports the old format.
> > > > >
> > > > > [Miguel Gazquez: Rebased + made driver work with or without
> > > > > DRM_BRIDGE_ATTACH_NO_CONNECTOR]
> > > >
> > > > What is the use case for not using DRM_BRIDGE_ATTACH_NO_CONNECTOR?
> > >
> > > Some display controller drivers (like the tilcdc) call drm_bridge_attach
> > > without DRM_BRIDGE_ATTACH_NO_CONNECTOR, so the bridge must support both with
> > > and without DRM_BRIDGE_ATTACH_NO_CONNECTOR to be compatible with all display
> > > controllers.
> >
> > I'd rather convert tilcdc to use DRM_BRIDGE_ATTACH_NO_CONNECTOR then.
>
> The problem is that doing that break devicetrees using the tilcdc and a
> bridge who doesn't support DRM_BRIDGE_ATTACH_NO_CONNECTOR (there are
> multiple bridges that don't support DRM_BRIDGE_ATTACH_NO_CONNECTOR), and if
> my understanding is correct breaking devicetrees is not allowed.

How does it break devicetree? The drm_bridge_connector isn't a part of
DT.

--
With best wishes
Dmitry