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authorChen Yu <yu.c.chen@intel.com>2017-04-09 08:45:16 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-04-13 04:38:44 +0300
commitc4a3fa261b16858416f1fd7db03a33d7ef5fc0b3 (patch)
treeb43cc679de238a831587d9e2809f954f0304ece9 /drivers
parent39da7c509acff13fc8cb12ec1bb20337c988ed36 (diff)
downloadlinux-c4a3fa261b16858416f1fd7db03a33d7ef5fc0b3.tar.xz
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')
-rw-r--r--drivers/cpufreq/cpufreq.c18
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;