From: Maxime Ripard <maxime@cerno.tech>
To: Jagan Teki <jagan@amarulasolutions.com>
Cc: Chen-Yu Tsai <wens@csie.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Neil Armstrong <narmstrong@baylibre.com>,
Robert Foss <robert.foss@linaro.org>,
Sam Ravnborg <sam@ravnborg.org>,
dri-devel@lists.freedesktop.org,
linux-arm-kernel@lists.infradead.org,
linux-sunxi@googlegroups.com, linux-amarula@amarulasolutions.com
Subject: Re: [PATCH v6 1/6] drm: sun4i: dsi: Drop DRM bind race with bridge attach
Date: Wed, 2 Feb 2022 09:59:36 +0100 [thread overview]
Message-ID: <20220202085936.ogxhpl7u42lubhdd@houat> (raw)
In-Reply-To: <CAMty3ZAetcXpcokJ418VGHzbi4ivJg4Rt0OVgh7WaZ6GAJQY1Q@mail.gmail.com>
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On Mon, Jan 17, 2022 at 09:12:37PM +0530, Jagan Teki wrote:
> On Mon, Dec 13, 2021 at 10:32 PM Maxime Ripard <maxime@cerno.tech> wrote:
> >
> > On Fri, Dec 10, 2021 at 04:47:06PM +0530, Jagan Teki wrote:
> > > Existing host driver will keep looking for DRM pointer in
> > > sun6i_dsi_attach and defers even if the particular DSI device
> > > is found for the first time. Meanwhile it triggers the bind
> > > callback and gets the DRM pointer and then continues the
> > > sun6i_dsi_attach.
> > >
> > > This makes a deadlock situation if sun6i_dsi_attach is trying
> > > to find the bridge.
> >
> > I'm not sure what you mean by deadlock here, there's no lock involved?
>
> deadlock parse here for general understanding, where bind is trying to
> attach bridge but drm pointer is not available that point and drm
> pointer will available only when bind done. This is what I'm calling
> as deadlock here.
Have you read:
https://www.kernel.org/doc/html/latest/gpu/drm-kms-helpers.html#special-care-with-mipi-dsi-bridges
Maxime
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next prev parent reply other threads:[~2022-02-02 9:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 11:17 [PATCH v6 0/6] drm: sun4i: dsi: Bridge support Jagan Teki
2021-12-10 11:17 ` [PATCH v6 1/6] drm: sun4i: dsi: Drop DRM bind race with bridge attach Jagan Teki
2021-12-13 17:02 ` Maxime Ripard
2022-01-17 15:42 ` Jagan Teki
2022-02-02 8:59 ` Maxime Ripard [this message]
2021-12-10 11:17 ` [PATCH v6 2/6] drm: sun4i: dsi: Add component only once DSI device attached Jagan Teki
2021-12-13 17:05 ` Maxime Ripard
2021-12-10 11:17 ` [PATCH v6 3/6] drm: sun4i: dsi: Add bridge support Jagan Teki
2021-12-13 17:17 ` Maxime Ripard
2022-01-17 15:38 ` Jagan Teki
2021-12-10 11:17 ` [DO NOT MERGE] [PATCH v6 4/6] ARM: dts: sun8i: bananapi-m2m: Enable iS070WV20-CT16 DSI Panel Jagan Teki
2021-12-10 11:17 ` [DO NOT MERGE] [PATCH v6 5/6] ARM: dts: sun8i: bananapi-m2m: Enable ICN6211 DSI Bridge Jagan Teki
2021-12-10 11:17 ` [DO NOT MERGE] [PATCH v6 6/6] ARM: dts: sun8i: bananapi-m2m: Enable DLPC3433 Bridge (I2C) Jagan Teki
2021-12-13 17:00 ` [PATCH v6 0/6] drm: sun4i: dsi: Bridge support Maxime Ripard
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