From: "Bjørn Mork" <bjorn@mork.no>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH Resend] cpufreq: remove sysfs files for CPU which failed to come back after resume
Date: Mon, 23 Dec 2013 07:55:50 +0100 [thread overview]
Message-ID: <87d2kokqdl.fsf@nemi.mork.no> (raw)
In-Reply-To: <CAKohpok1dGMPSAehwsVeiyHzxaHupenA4sP5cxCrjVYQMyrVWA@mail.gmail.com> (Viresh Kumar's message of "Mon, 23 Dec 2013 11:32:28 +0530")
Viresh Kumar <viresh.kumar@linaro.org> writes:
> On 23 December 2013 11:25, Bjørn Mork <bjorn@mork.no> wrote:
>> I can confirm that it fixes the major regression. With this branch, the
>> cpufreq directory is completely removed after a cancelled userspace
>> hibernate (with the acpi-cpufreq problem causing failure). So it is
>> possible to restore cpufreq by manually offlining and onlining non-boot
>> cores. No more leftover sysfs attributes.
>
> Thanks for giving it a try once again :)
>
>> But there is still a minor regression compared to the old (v3.11)
>> behaviour: Previously the cpufreq functionality would be automatically
>> restored by any completed hibernate or suspend cycle, since it would
>> effectively do the CPU offline/online. This automatix fixup won't happen
>> with the current pm-cpufreq branch.
>
> I didn't understood it completely, sorry :)
>
> As far as I can see from 3.11 code we simply used to fail with any failure
> resulting with a call to ->init() or some other call..
>
> And so cpufreq wouldn't have added any directories at all in that case.
> And so I think we still required an offline/online sequence to guarantee
> things..
That's correct. The immediate result of the failure is exactly the
same.
The difference is that a subsequent resume would restore the cpufreq
device whether it existed or not. That made a complete suspend/resume
fix up any missing cpufreq device, e.g. one that was removed by a
previous error.
One effect of saving state on suspend is that a missing device isn't
added on resume. You can of course see that as a feature. But to me
it's a regression, because:
- it didn't use to work that way, and
- the addition of missing devices on resume is always wanted AFAICS.
Bjørn
WARNING: multiple messages have this Message-ID (diff)
From: "Bjørn Mork" <bjorn@mork.no>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
"cpufreq\@vger.kernel.org" <cpufreq@vger.kernel.org>,
"linux-pm\@vger.kernel.org" <linux-pm@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH Resend] cpufreq: remove sysfs files for CPU which failed to come back after resume
Date: Mon, 23 Dec 2013 07:55:50 +0100 [thread overview]
Message-ID: <87d2kokqdl.fsf@nemi.mork.no> (raw)
In-Reply-To: <CAKohpok1dGMPSAehwsVeiyHzxaHupenA4sP5cxCrjVYQMyrVWA@mail.gmail.com> (Viresh Kumar's message of "Mon, 23 Dec 2013 11:32:28 +0530")
Viresh Kumar <viresh.kumar@linaro.org> writes:
> On 23 December 2013 11:25, Bjørn Mork <bjorn@mork.no> wrote:
>> I can confirm that it fixes the major regression. With this branch, the
>> cpufreq directory is completely removed after a cancelled userspace
>> hibernate (with the acpi-cpufreq problem causing failure). So it is
>> possible to restore cpufreq by manually offlining and onlining non-boot
>> cores. No more leftover sysfs attributes.
>
> Thanks for giving it a try once again :)
>
>> But there is still a minor regression compared to the old (v3.11)
>> behaviour: Previously the cpufreq functionality would be automatically
>> restored by any completed hibernate or suspend cycle, since it would
>> effectively do the CPU offline/online. This automatix fixup won't happen
>> with the current pm-cpufreq branch.
>
> I didn't understood it completely, sorry :)
>
> As far as I can see from 3.11 code we simply used to fail with any failure
> resulting with a call to ->init() or some other call..
>
> And so cpufreq wouldn't have added any directories at all in that case.
> And so I think we still required an offline/online sequence to guarantee
> things..
That's correct. The immediate result of the failure is exactly the
same.
The difference is that a subsequent resume would restore the cpufreq
device whether it existed or not. That made a complete suspend/resume
fix up any missing cpufreq device, e.g. one that was removed by a
previous error.
One effect of saving state on suspend is that a missing device isn't
added on resume. You can of course see that as a feature. But to me
it's a regression, because:
- it didn't use to work that way, and
- the addition of missing devices on resume is always wanted AFAICS.
Bjørn
next prev parent reply other threads:[~2013-12-23 6:55 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-20 15:56 [PATCH Resend] cpufreq: remove sysfs files for CPU which failed to come back after resume Viresh Kumar
2013-12-20 15:56 ` Viresh Kumar
2013-12-22 1:00 ` Rafael J. Wysocki
2013-12-22 1:00 ` Rafael J. Wysocki
2013-12-23 5:55 ` Bjørn Mork
2013-12-23 5:55 ` Bjørn Mork
2013-12-23 6:02 ` Viresh Kumar
2013-12-23 6:55 ` Bjørn Mork [this message]
2013-12-23 6:55 ` Bjørn Mork
2013-12-23 7:55 ` viresh kumar
2013-12-23 9:23 ` Bjørn Mork
2013-12-23 9:23 ` Bjørn Mork
2013-12-23 10:45 ` Viresh Kumar
2013-12-23 10:57 ` Bjørn Mork
2013-12-23 10:57 ` Bjørn Mork
2013-12-23 11:13 ` Viresh Kumar
2013-12-23 11:42 ` Bjørn Mork
2013-12-23 11:42 ` Bjørn Mork
2013-12-23 15:45 ` viresh kumar
2013-12-23 15:45 ` viresh kumar
2013-12-24 0:35 ` Rafael J. Wysocki
2013-12-24 0:35 ` Rafael J. Wysocki
2013-12-24 0:27 ` Viresh Kumar
2013-12-24 0:43 ` Rafael J. Wysocki
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