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

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Date:   Thu, 10 Jun 2021 13:19:05 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     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>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cpufreq: cppc: Mark frequency invariance broken

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?

> ---
> Rafael, please apply this for v5.13-rc if it looks fine to you.
>
>  drivers/cpufreq/Kconfig.arm | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
> index a5c5f70acfc9..614c34350f41 100644
> --- a/drivers/cpufreq/Kconfig.arm
> +++ b/drivers/cpufreq/Kconfig.arm
> @@ -22,6 +22,7 @@ config ACPI_CPPC_CPUFREQ
>  config ACPI_CPPC_CPUFREQ_FIE
>         bool "Frequency Invariance support for CPPC cpufreq driver"
>         depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY
> +       depends on BROKEN
>         default y
>         help
>           This extends frequency invariance support in the CPPC cpufreq driver,
> --
> 2.31.1.272.g89b43f80a514
>