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Date:   Thu, 03 Aug 2023 20:46:55 +0000
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
From:   Simon Ser <contact@emersion.fr>
Cc:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Andrzej Hajda <andrzej.hajda@intel.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Robert Foss <rfoss@kernel.org>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Janne Grunau <j@jannau.net>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?utf-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        Harry Wentland <harry.wentland@amd.com>,
        Leo Li <sunpeng.li@amd.com>,
        Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>,
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        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Jani Nikula <jani.nikula@linux.intel.com>,
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        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 3/4] drm/uapi: document the USB subconnector type
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In-Reply-To: <20230803204459.GD27752@pendragon.ideasonboard.com>
References: <20230729004913.215872-1-dmitry.baryshkov@linaro.org> <20230729004913.215872-4-dmitry.baryshkov@linaro.org> <20230802185547.GC32500@pendragon.ideasonboard.com> <a32ce695-038f-0ef8-3584-5bd1ba528131@linaro.org> <20230802191351.GA1407@pendragon.ideasonboard.com> <DE2B4523-D16C-4AFC-8352-212B23548DD5@linaro.org> <b6oOVz2YMIG4hJDWhq9lTh6R2HYcrpRwHENhplig9KSQMD8dIjTgC5KdH1Ij3URgV2HESp67Ax7QUsByGjMLouvbs-5q7PiPRdLkgJz6Fwk=@emersion.fr> <ADjuOeqA6575DKutMPaR9mW9rLhm-wjLc4ruoUkNwImf-GB90FdwDB7v7y6LFdzVG3BC4R52A0RUtStK4_smmGYTUs3UPDOX4T4Zl2YHkxE=@emersion.fr> <20230803204459.GD27752@pendragon.ideasonboard.com>
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On Thursday, August 3rd, 2023 at 22:44, Laurent Pinchart <laurent.pinchart@=
ideasonboard.com> wrote:

> On Thu, Aug 03, 2023 at 03:31:16PM +0000, Simon Ser wrote:
>=20
> > On Thursday, August 3rd, 2023 at 17:22, Simon Ser contact@emersion.fr w=
rote:
> >=20
> > > The KMS docs describe "subconnector" to be defined as "downstream por=
t" for DP.
> > > Can USB-C (or USB) be seen as a DP downstream port?
> >=20
> > 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.
>=20
> Doesn't this contradict the example use case you gave in your previous
> e-mail, with wlroots stating "DP-3 via DVI-D" ? I understand that as DP
> carried over a DVI-D physical connector, did I get it wrong ?

No, this is DVI carried over DP. DP cannot be carried over VGA/DVI/HDMI,
but VGA/DVI/HDMI can be carried over DP.