Hello Chaoyi,

On Mon, Mar 30, 2026 at 09:34:15AM +0800, Chaoyi Chen wrote:
> > There are two parts, which possibly need some discussion:
> > 
> >  1. I added a dedicated bridge callback for out-of-band hotplug events,
> >     which is separate from the hotplug_notify. I have a feeling, that
> >     there might be a better solution, but haven't found it.
> 
> Could you explain what an out-of-band hotplug event is?
> 
> Can't the drivers/usb/typec/altmodes/displayport.c respond to these
> hot-plug events? Thank you.

That is what generates the out-of-band hotplug event in the first
place via drm_connector_oob_hotplug_event(). The oob in that call
means out of band.

If you look at that function it calls oob_hotplug_event() callback
on the DRM connector, which is then implemented by
drm_bridge_connector_oob_hotplug_event(). This function calls uses
the normal hpd handling (shared by in-band and out-of-band) and I'm
patching it, so that the bridges are aware of hpd explicitly being
provided out-of-band.

Greetings,

-- Sebastian