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

From: Simon Ser
Date: Fri Aug 18 2023 - 02:38:27 EST


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.

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