On Tue, 10 Sep 2013, Viresh Kumar wrote:
> On 9 September 2013 20:41, Guennadi Liakhovetski <g.liakhovetski@xxxxxx> wrote:
> > Sorry guys, I'm trying my best to stop this patch from propagating to
> > stable and to get it fixed asap, so, the CC list might be a bit excessive.
> > Also trying to fix the originally spare cc list, which makes it impossible
> > for me to reply to the original thread, instead have to start a new one.
> >
> > Commit
> >
> > commit dceff5ce18801dddc220d6238628619c93bc3cb6
> > Author: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> > Date: Sun Sep 1 22:19:37 2013 +0530
> >
> > cpufreq: fix serialization issues with freq change notifiers
> >
> > breaks .transition_ongoing counting. This leads to cpufreq-cpu0 not
> > working any more. In particular switching the governor from performance to
> > powersave directly after boot doesn't result in a frequency switch any
> > more. Reverting this patch fixes the problem again. Tested with today's
> > -next.
>
> I have tested it again on my exynos and intel machines and couldn't see
> a single problem with this patch..
Ok, here's what I've just done.
1. checkout -next tag next-20130909
commit 98926a8004b453089368fda456b8c869240e9953
Author: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Date: Mon Sep 9 16:05:53 2013 +1000
Add linux-next specific files for 20130909
2. built and booted a kernel for kzm9g (.config available on request)
3. cpufreq failed to initialise:
cpufreq_cpu0: failed to find cpu0 node
cpufreq-cpu0: probe of cpufreq-cpu0 failed with error -2
due to commit f837a9b5ab05c52a07108c6f09ca66f2e0aee757 - as reported in
another thread.
4. reverted that commit, resolving a trivial conflict. Added a debug
output in __cpufreq_driver_target() of
if (cpufreq_disabled())
return -ENODEV;
+ pr_info("%s() %d\n", __func__, policy->transition_ongoing);
if (policy->transition_ongoing)
return -EBUSY;
Built and booted, got
cpufreq: __cpufreq_driver_target(): 1
printed out 4 times from the beginning.
5. tried
echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
the above output appeared 2 more times - no frequency change resulted.
6. reverted commit dceff5ce18801dddc220d6238628619c93bc3cb6, built booted
- cpufreq works again.
> I am afraid you need to give us some more information on how it broke
> your stuff.. :)
Hope the above is enough.
Thanks
Guennadi
> And I am also not sure cpufreq-cpu0 is different then any other driver..
>
> --
> viresh
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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