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Date:   Thu, 03 Aug 2023 15:31:16 +0000
To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
From:   Simon Ser <contact@emersion.fr>
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Subject: Re: [PATCH 3/4] drm/uapi: document the USB subconnector type
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On Thursday, August 3rd, 2023 at 17:22, Simon Ser <contact@emersion.fr> wro=
te:

> The KMS docs describe "subconnector" to be defined as "downstream port" f=
or DP.
> Can USB-C (or USB) be seen as a DP downstream port?

To expand on this a bit: I'm wondering if we're mixing apples and
oranges here. The current values of "subconnector" typically describe
the lower-level protocol tunneled inside DP. For instance, VGA can be
tunneled inside the DP cable when using DP =E2=86=92 VGA adapter.

However, in the USB-C case, DP itself is tunneled inside USB-C. And you
might use a USB-C =E2=86=92 DP adapter. So it's not really *sub*connector, =
it's
more of a *super*connector, right?

I think [1] is somewhat related, since it also allows user-space to
discover whether a connector uses USB-C. But relying on sysfs to figure
this out isn't super optimal perhaps.

[1]: https://lore.kernel.org/dri-devel/20221108185004.2263578-1-wonchung@go=
ogle.com/