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From:   Bjorn Andersson <bjorn.andersson@linaro.org>
Date:   Mon, 2 May 2022 19:03:22 -0500
Message-ID: <CAOCOHw6QnJZZWmPCzF=tBidiuDrQ75YWPQhdujfmwRpqjOw4xA@mail.gmail.com>
Subject: Re: [PATCH 2/2] Revert "drm: of: Lookup if child node has panel or bridge"
To:     Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Cc:     Maxime Ripard <maxime@cerno.tech>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Jagan Teki <jagan@amarulasolutions.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Thierry Reding <thierry.reding@gmail.com>,
        Rob Clark <robdclark@gmail.com>, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        Linus Walleij <linus.walleij@linaro.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robert Foss <robert.foss@linaro.org>
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On Wed, Apr 27, 2022 at 2:34 AM Paul Kocialkowski
<paul.kocialkowski@bootlin.com> wrote:
>
> Hi Bjorn,
>
> On Tue 26 Apr 22, 14:10, Bjorn Andersson wrote:
> > On Tue 26 Apr 06:50 PDT 2022, Paul Kocialkowski wrote:
[..]
> > > Bjorn, what do you think?
> > >
> >
> > I'm okay with the idea that it's up the driver to check that the output
> > port references an usb-c-connector - either before the call or upon
> > drm_of_find_panel_or_bridge() returning an error.
>
> Actually I'm starting to think might be wrong on this one: there's a
> display-connector bridge driver that should register a bridge, so
> drm_of_find_panel_or_bridge should work. Did you have that driver enabled?
>

I don't have this driver enabled, but that seems like it would solve
the problem when the remote node is a dp-connector.

Unfortunately in my particular case, I have a usb-c-connector. So I
don't see that I would be able to reuse this straight off.
But I assume that this is trying to say that the USB Type-C code is
supposed to provide a bridge for each of the connectors exposed by my
USB Type-C controller?

I've been building on top of drm_connector_oob_hotplug_event() to
achieve this (with the link in the other direction)...

Regards,
Bjorn