linux-kernel - Re: cpufreq/thermal regression in 6.10

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Date: Tue, 11 Jun 2024 14:02:15 +0200
From: Johan Hovold <johan@...nel.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	Zhang Rui <rui.zhang@...el.com>, Lukasz Luba <lukasz.luba@....com>,
	Steev Klimaszewski <steev@...i.org>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, regressions@...ts.linux.dev
Subject: Re: cpufreq/thermal regression in 6.10

On Tue, Jun 11, 2024 at 12:54:25PM +0200, Rafael J. Wysocki wrote:
> On Mon, Jun 10, 2024 at 1:17 PM Rafael J. Wysocki <rafael@...nel.org> wrote:
> > On Sun, Jun 9, 2024 at 9:53 AM Johan Hovold <johan@...nel.org> wrote:

> > > Steev reported to me off-list that the CPU frequency of the big cores on
> > > the Lenovo ThinkPad X13s sometimes appears to get stuck at a low
> > > frequency with 6.10-rc2.
> > >
> > > I just confirmed that once the cores are fully throttled (using the
> > > stepwise thermal governor) due to the skin temperature reaching the
> > > first trip point, scaling_max_freq gets stuck at the next OPP:
> > >
> > >         cpu4/cpufreq/scaling_max_freq:940800
> > >         cpu5/cpufreq/scaling_max_freq:940800
> > >         cpu6/cpufreq/scaling_max_freq:940800
> > >         cpu7/cpufreq/scaling_max_freq:940800
> > >
> > > when the temperature drops again.

> If this is the step-wise governor, the problem might have been
> introduced by commit
> 
> 042a3d80f118 thermal: core: Move passive polling management to the core
> 
> which removed passive polling count updates from that governor, so if
> the thermal zone in question has passive polling only and no regular
> polling, temperature updates may stop coming before the governor drops
> the cooling device states to the "no target" level.
> 
> So please test the attached partial revert of the above commit when you can.

Thanks for the quick fix. The partial revert seems to do the trick:

Tested-by: Johan Hovold <johan+linaro@...nel.org>

Johan