Messages in this thread | | | From | Bjørn Mork <> | Subject | Re: [PATCH Resend] cpufreq: remove sysfs files for CPU which failed to come back after resume | Date | Mon, 23 Dec 2013 11:57:12 +0100 |
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Viresh Kumar <viresh.kumar@linaro.org> writes: > On 23 December 2013 14:53, Bjørn Mork <bjorn@mork.no> wrote: > >> But if you really want to implement suspend/resume, then you >> do need to keep the whole device and not just the sysfs files. Keeping >> the attribute files allow you to save and restore changed permissions, >> but it doesn't save any user modified settings. > > Which settings are you talking about? I thought we are preserving all > files..
I could be missing something, but I haven't noticed any attempt to preserve anything except the sysfs files.
I tried modifying the max frequency, using
echo 800000 >/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq echo 800000 >/sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq
After supend + resume the boot CPU still had the modifed maximum, while the non-boot core was reset to the default value. I changed the gid of both files too, verifying that they were saved and restored as expected. But the value will change to default.
IMHO it would still be a lot better if this was handled as a true hotplug event, allowing userspace to reset values/modes/owners on resume. Hiding the hotplug event and saving part of the userspace controlled environment is worse than not doing anything at all.
Bjørn -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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