From: Viresh Kumar <viresh.kumar@linaro.org>
To: "Chun-Jen Tseng (曾俊仁)" <Chun-Jen.Tseng@mediatek.com>
Cc: "cw00.choi@samsung.com" <cw00.choi@samsung.com>,
"rafael@kernel.org" <rafael@kernel.org>,
Project_Global_Chrome_Upstream_Group
<Project_Global_Chrome_Upstream_Group@mediatek.com>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com>,
"myungjoo.ham@samsung.com" <myungjoo.ham@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kyungmin.park@samsung.com" <kyungmin.park@samsung.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH v3 1/3] cpufreq: mediatek: using global lock avoid race condition
Date: Wed, 16 Apr 2025 13:35:17 +0530 [thread overview]
Message-ID: <20250416080517.feansrkpycsynk6t@vireshk-i7> (raw)
In-Reply-To: <06356a55cdb3c34dfc716349d1967f95655b0ab2.camel@mediatek.com>
On 14-04-25, 08:42, Chun-Jen Tseng (曾俊仁) wrote:
> Hi Viresh,
>
> The CCI level choose by Max_Level(LCPU & BCPU frequency) in devfreq
> driver.
> without global lock, It may choose wrong CCI level and cause system
> stall.
>
> I hope this flow is serial setting like, BCPU / LCPU set frequency ->
> set CCI level -> BCPU / LCPU set frequency -> set CCI level -> ......
>
> without global lock, it could be LCPU / BCPU set frequency -> set CCI
> level(during this time, it may change BCPU / LCPU frequency and cause
> system stall.
>
> I also can only do global lock on ccifreq_support SoC.
As explained earlier, I don't think there is a race here. May be I am
wrong. And so I need a clear code path example from you, which proves
that there is a race here.
--
viresh
next prev parent reply other threads:[~2025-04-16 8:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-14 7:43 [PATCH v3 0/3] fixed mediatek-cpufreq has multi policy concurrency issue Mark Tseng
2025-02-14 7:43 ` [PATCH v3 1/3] cpufreq: mediatek: using global lock avoid race condition Mark Tseng
2025-02-19 5:42 ` Viresh Kumar
2025-03-20 8:22 ` Chun-Jen Tseng (曾俊仁)
2025-03-21 4:56 ` Viresh Kumar
2025-03-21 5:32 ` Chun-Jen Tseng (曾俊仁)
2025-03-21 6:01 ` Viresh Kumar
2025-03-24 3:21 ` Chun-Jen Tseng (曾俊仁)
2025-03-24 5:43 ` Viresh Kumar
2025-04-14 8:42 ` Chun-Jen Tseng (曾俊仁)
2025-04-16 8:05 ` Viresh Kumar [this message]
2025-08-28 13:26 ` Chen-Yu Tsai
2025-08-29 5:47 ` Viresh Kumar
2025-02-19 7:23 ` Dan Carpenter
2025-03-20 8:25 ` Chun-Jen Tseng (曾俊仁)
2025-02-14 7:43 ` [PATCH v3 2/3] cpufreq: mediatek: Add CPUFREQ_ASYNC_NOTIFICATION flag Mark Tseng
2025-02-19 5:45 ` Viresh Kumar
2025-03-20 8:34 ` Chun-Jen Tseng (曾俊仁)
2025-03-21 4:59 ` Viresh Kumar
2025-02-14 7:43 ` [PATCH v3 3/3] cpufreq: mediatek: data safety protect Mark Tseng
2025-02-19 5:49 ` Viresh Kumar
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