Messages in this thread | | | Date | Tue, 10 Sep 2013 17:12:14 +0200 (CEST) | From | Guennadi Liakhovetski <> | Subject | Re: "cpufreq: fix serialization issues with freq change notifiers" breaks cpufreq too |
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On Tue, 10 Sep 2013, Viresh Kumar wrote:
> On 9 September 2013 20:41, Guennadi Liakhovetski <g.liakhovetski@gmx.de> 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@linaro.org> > > 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@canb.auug.org.au> 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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