linux-kernel - Re: [PATCH] cpufreq: cppc: Mark frequency invariance broken

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Date:   Thu, 10 Jun 2021 14:30:29 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Rafael Wysocki <rjw@...ysocki.net>,
        Ionela Voinescu <ionela.voinescu@....com>,
        Linux PM <linux-pm@...r.kernel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Qian Cai <quic_qiancai@...cinc.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: cppc: Mark frequency invariance broken

On Thu, Jun 10, 2021 at 1:34 PM Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> On 10-06-21, 13:19, Rafael J. Wysocki wrote:
> > On Thu, Jun 10, 2021 at 9:58 AM Viresh Kumar <viresh.kumar@...aro.org> wrote:
> > >
> > > There are few races in the frequency invariance support for CPPC driver,
> > > namely the driver doesn't stop the kthread_work and irq_work on policy
> > > exit during suspend/resume or CPU hotplug.
> > >
> > > A proper fix won't be possible for the 5.13-rc, as it requires a lot of
> > > changes. Instead of reverting the patch, mark this feature BROKEN for
> > > now.
> > >
> > > Fixes: 4c38f2df71c8 ("cpufreq: CPPC: Add support for frequency invariance")
> > > Reported-by: Qian Cai <quic_qiancai@...cinc.com>
> > > Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> >
> > Well, why don't we revert 4c38f2df71c8 instead?
> >
> > Is there any particular reason for retaining it?
>
> I was just trying to reduce the diff size here, since this feature
> (which broke) was controlled by a CONFIG option, it looked like a nice
> way of doing it.
>
> It was already reviewed and a diff over it should be easier to review.
>
> I can do a full revert if that's what you want.

I would prefer a full revert TBH.

Making a new feature depend on BROKEN feels like it shouldn't have
been added at this point in the first place.