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Subject: Re: [PATCH v4] clk: mediatek: Do a runtime PM get on controllers during probe
From: Stephen Boyd <sboyd@kernel.org>
Cc: Chen-Yu Tsai <wenst@chromium.org>, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, Pin-yen Lin <treapking@chromium.org>, Weiyi Lu <weiyi.lu@mediatek.com>, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Bosi Zhang <u201911157@hust.edu.cn>, Nicolas Boichat <drinkcat@chromium.org>, Uwe =?utf-8?q?Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>, Matthias Brugger <matthias.bgg@gmail.com>, Michael Turquette <mturquette@baylibre.com>, Pin-yen Lin <treapking@chromium.org>
Date: Wed, 10 Apr 2024 20:48:45 -0700
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Quoting Pin-yen Lin (2024-03-12 04:51:55)
> mt8183-mfgcfg has a mutual dependency with genpd during the probing
> stage, which leads to a deadlock in the following call stack:
>=20
> CPU0:  genpd_lock --> clk_prepare_lock
> genpd_power_off_work_fn()
>  genpd_lock()
>  generic_pm_domain::power_off()
>     clk_unprepare()
>       clk_prepare_lock()
>=20
> CPU1: clk_prepare_lock --> genpd_lock
> clk_register()
>   __clk_core_init()
>     clk_prepare_lock()
>     clk_pm_runtime_get()
>       genpd_lock()
>=20
> Do a runtime PM get at the probe function to make sure clk_register()
> won't acquire the genpd lock. Instead of only modifying mt8183-mfgcfg,
> do this on all mediatek clock controller probings because we don't
> believe this would cause any regression.
>=20
> Verified on MT8183 and MT8192 Chromebooks.
>=20
> Fixes: acddfc2c261b ("clk: mediatek: Add MT8183 clock support")
> Signed-off-by: Pin-yen Lin <treapking@chromium.org>
>=20
> ---

Applied to clk-fixes