linux-kernel - Re: [PATCH v2 2/2] cpufreq: mediatek-hw: Wait for CPU supplies before probing

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Message-ID: <20240123060951.2m6h6t537bu27ois@vireshk-i7>
Date: Tue, 23 Jan 2024 11:39:51 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Nícolas F. R. A. Prado <nfraprado@...labora.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Matthias Brugger <matthias.bgg@...il.com>, kernel@...labora.com,
	"Hector.Yuan" <hector.yuan@...iatek.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-mediatek@...ts.infradead.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 2/2] cpufreq: mediatek-hw: Wait for CPU supplies
 before probing

On 10-01-24, 11:23, Nícolas F. R. A. Prado wrote:
> Before proceeding with the probe and enabling frequency scaling for the
> CPUs, make sure that all supplies feeding the CPUs have probed.
> 
> This fixes an issue observed on MT8195-Tomato where if the
> mediatek-cpufreq-hw driver enabled the hardware (by writing to
> REG_FREQ_ENABLE) before the SPMI controller driver (spmi-mtk-pmif),
> behind which lies the big CPU supply, probed the platform would hang
> shortly after with "rcu: INFO: rcu_preempt detected stalls on
> CPUs/tasks" being printed in the log.
> 
> Fixes: 4855e26bcf4d ("cpufreq: mediatek-hw: Add support for CPUFREQ HW")
> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>

Applied 2/2. Thanks.

-- 
viresh