linux-kernel - Re: [RFT][PATCH 0/2] cpufreq: intel_pstate: Handle _PPC updates on global turbo disable/enable

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Date:   Sun, 3 Mar 2019 18:03:52 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Chen Yu <yu.c.chen@...el.com>,
        Gabriele Mazzotta <gabriele.mzt@...il.com>
Subject: Re: [RFT][PATCH 0/2] cpufreq: intel_pstate: Handle _PPC updates on
 global turbo disable/enable

On Fri, Mar 1, 2019 at 6:39 PM Srinivas Pandruvada
<srinivas.pandruvada@...ux.intel.com> wrote:
>
> On Fri, 2019-03-01 at 13:43 +0100, Rafael J. Wysocki wrote:
> > Hi All,
> >
> > This is how I would fix the issue reported in BZ 200759 (see this
> > patch series
> > from Yu too: https://marc.info/?l=linux-pm&m=155137672924029&w=2).
> >
> > Patch [1/2] causes intel_pstate to update all policies if it gets a
> > _PPC change
> > notification and sees a global turbo disable/enable change.
> >
> > Patch [2/2] makes it update cpuinfo.max_freq for all policies in
> > those cases.
> >
> > The patches here have not been tested yet, so testing would be much
> > appreciated.
> >
> > Of course, comments are welcome too!
>
> This is the only platform, someone reported such issue.

I don't think this matters.

First, it doesn't mean that no other problems have this problem.

Second, the current handling of MSR_IA32_MISC_ENABLE_TURBO_DISABLE
changes in intel_pstate is not sufficient if the changes is from set
to unset anyway.