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From:   John Stultz <john.stultz@linaro.org>
Date:   Wed, 29 Sep 2021 16:29:42 -0700
Message-ID: <CALAqxLW=dJSmfaHAL=BfYVVxZHQvzJWu4UjMixwgM=Nh85JVNw@mail.gmail.com>
Subject: Re: [PATCH v4 00/24] drm/bridge: Make panel and bridge probe order consistent
To:     Maxime Ripard <maxime@cerno.tech>
Cc:     Andrzej Hajda <a.hajda@samsung.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Daniel Vetter <daniel.vetter@intel.com>,
        David Airlie <airlied@linux.ie>,
        Jonas Karlman <jonas@kwiboo.se>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Robert Foss <robert.foss@linaro.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Sean Paul <sean@poorly.run>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <freedreno@lists.freedesktop.org>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        lkml <linux-kernel@vger.kernel.org>,
        Xinliang Liu <xinliang.liu@linaro.org>,
        Seung-Woo Kim <sw0312.kim@samsung.com>,
        Tian Tao <tiantao6@hisilicon.com>,
        Inki Dae <inki.dae@samsung.com>,
        Linux Samsung SOC <linux-samsung-soc@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Rob Clark <robdclark@gmail.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Chen Feng <puck.chen@hisilicon.com>,
        Xinwei Kong <kong.kongxinwei@hisilicon.com>,
        Joonyoung Shim <jy0922.shim@samsung.com>
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On Wed, Sep 29, 2021 at 2:51 PM John Stultz <john.stultz@linaro.org> wrote:
>
> On Wed, Sep 29, 2021 at 2:32 PM John Stultz <john.stultz@linaro.org> wrote:
> > On Wed, Sep 29, 2021 at 2:27 PM John Stultz <john.stultz@linaro.org> wrote:
> > > On Fri, Sep 10, 2021 at 3:12 AM Maxime Ripard <maxime@cerno.tech> wrote:
> > > > The best practice to avoid those issues is to register its functions only after
> > > > all its dependencies are live. We also shouldn't wait any longer than we should
> > > > to play nice with the other components that are waiting for us, so in our case
> > > > that would mean moving the DSI device registration to the bridge probe.
> > > >
> > > > I also had a look at all the DSI hosts, and it seems that exynos, kirin and msm
> > > > would be affected by this and wouldn't probe anymore after those changes.
> > > > Exynos and kirin seems to be simple enough for a mechanical change (that still
> > > > requires to be tested), but the changes in msm seemed to be far more important
> > > > and I wasn't confortable doing them.
> > >
> > >
> > > Hey Maxime,
> > >   Sorry for taking so long to get to this, but now that plumbers is
> > > over I've had a chance to check it out on kirin
> > >
> > > Rob Clark pointed me to his branch with some fixups here:
> > >    https://gitlab.freedesktop.org/robclark/msm/-/commits/for-mripard/bridge-rework
> > >
> > > But trying to boot hikey with that, I see the following loop indefinitely:
> > > [    4.632132] adv7511 2-0039: supply avdd not found, using dummy regulator
> > > [    4.638961] adv7511 2-0039: supply dvdd not found, using dummy regulator
> > > [    4.645741] adv7511 2-0039: supply pvdd not found, using dummy regulator
> > > [    4.652483] adv7511 2-0039: supply a2vdd not found, using dummy regulator
> > > [    4.659342] adv7511 2-0039: supply v3p3 not found, using dummy regulator
> > > [    4.666086] adv7511 2-0039: supply v1p2 not found, using dummy regulator
> > > [    4.681898] adv7511 2-0039: failed to find dsi host
> >
> > I just realized Rob's tree is missing the kirin patch. My apologies!
> > I'll retest and let you know.
>
> Ok, just retested including the kirin patch and unfortunately I'm
> still seeing the same thing.  :(
>
> Will dig a bit and let you know when I find more.

Hey Maxime!
  I chased down the issue. The dsi probe code was still calling
drm_of_find_panel_or_bridge() in order to succeed.

I've moved the logic that looks for the bridge into the bridge_init
and with that it seems to work.

Feel free (assuming it looks ok) to fold this change into your kirin patch:
  https://git.linaro.org/people/john.stultz/android-dev.git/commit/?id=4a35ccc4d7a53f68d6d93da3b47e232a7c75b91d

thanks
-john