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

From: Srinivas Pandruvada
Date: Fri Mar 01 2019 - 12:39:31 EST


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.
Can we solve this by some udev rules and offline/online cpu 1-3 on
power source change?

There are examples of changing governors on power source change.
https://bbs.archlinux.org/viewtopic.php?id=207186

Here instead of changing governor just
echo 0 > /sys/devices/system/cpu/cpu1/online
echo 1 > /sys/devices/system/cpu/cpu1/online
echo 0 >
/sys/devices/system/cpu/cpu2/online
echo 1 >
/sys/devices/system/cpu/cpu2/online
echo 0 >
/sys/devices/system/cpu/cpu3/online
echo 1 >
/sys/devices/system/cpu/cpu3/online

Thanks,
Srinivas

>
> Thanks,
> Rafael
>