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Chen Yu authored
commit c4a3fa26 upstream. There is a report that after commit 27622b06 ("cpufreq: Convert to hotplug state machine"), the normal CPU offline/online cycle fails on some platforms. According to the ftrace result, this problem was triggered on platforms using acpi-cpufreq as the default cpufreq driver, and due to the lack of some ACPI freq method (eg. _PCT), cpufreq_online() failed and returned a negative value, so the CPU hotplug state machine rolled back the CPU online process. Actually, from the user's perspective, the failure of cpufreq_online() should not prevent that CPU from being brought up, although cpufreq might not work on that CPU. BTW, during system startup cpufreq_online() is not invoked via CPU online but by the cpufreq device creation process, so the APs can be brought up even though cpufreq_online() fails in that stage. This patch ignores the return value of cpufreq_online/offline() and lets the cpufreq framework deal with the failure. cpufreq_online() itself will do a proper rollback in that case and if _PCT is missing, the ACPI cpufreq driver will print a warning if the corresponding debug options have been enabled. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=194581 Fixes: 27622b06 ("cpufreq: Convert to hotplug state machine") Reported-and-tested-by: Tomasz Maciej Nowak <tmn505@gmail.com> Signed-off-by: Chen Yu <yu.c.chen@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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