Re: [PATCH 3/4] drm/uapi: document the USB subconnector type

From: Dmitry Baryshkov
Date: Fri Aug 18 2023 - 06:34:13 EST


On 18/08/2023 09:24, Simon Ser wrote:
On Thursday, August 17th, 2023 at 21:33, Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> wrote:

We have been looking for a way to document that the corresponding DP
port is represented by the USB connector on the device.

Consequently, I believe the best way to document it, would be to use
DisplayPort / USB, when there is no dongle connected, switching to
DisplayPort / HDMI, DisplayPort / VGA, DisplayPort / DisplayPort, etc.
when the actual dongle / display is connected and then switching back to
the DisplayPort / USB when it gets disconnected.

If this sounds good to all parties, I'll post v2, adding this
explanation to the cover letter.

But how can user-space discover that the port is USB-C when it's
connected? That information is lost at this point.

Yes, unfortunately.

(In addition, this clashes with the existing semantics of the
subconnector prop as discussed before: USB-C is not sub-, it's super-.)

Ok. How do we proceed then? Is it fine to add another property for DP case? Do you have any particular property name in mind? I will follow with addition of this property then.

--
With best wishes
Dmitry