diff options
| author | Chen Yu <yu.c.chen@intel.com> | 2017-04-09 13:45:16 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2017-04-13 03:38:44 +0200 |
| commit | c4a3fa261b16858416f1fd7db03a33d7ef5fc0b3 (patch) | |
| tree | b43cc679de238a831587d9e2809f954f0304ece9 /drivers/cpufreq | |
| parent | 39da7c509acff13fc8cb12ec1bb20337c988ed36 (diff) | |
| download | linux-c4a3fa261b16858416f1fd7db03a33d7ef5fc0b3.tar.bz2 | |
cpufreq: Bring CPUs up even if cpufreq_online() failed
There is a report that after commit 27622b061eb4 ("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: 27622b061eb4 ("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>
Cc: 4.9+ <stable@vger.kernel.org> # 4.9+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index bc96d423781a..0e3f6496524d 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -2398,6 +2398,20 @@ EXPORT_SYMBOL_GPL(cpufreq_boost_enabled); *********************************************************************/ static enum cpuhp_state hp_online; +static int cpuhp_cpufreq_online(unsigned int cpu) +{ + cpufreq_online(cpu); + + return 0; +} + +static int cpuhp_cpufreq_offline(unsigned int cpu) +{ + cpufreq_offline(cpu); + + return 0; +} + /** * cpufreq_register_driver - register a CPU Frequency driver * @driver_data: A struct cpufreq_driver containing the values# @@ -2460,8 +2474,8 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data) } ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "cpufreq:online", - cpufreq_online, - cpufreq_offline); + cpuhp_cpufreq_online, + cpuhp_cpufreq_offline); if (ret < 0) goto err_if_unreg; hp_online = ret; |