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author | Bo Yan <byan@nvidia.com> | 2018-01-23 13:57:55 -0800 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2018-02-05 11:03:33 +0100 |
commit | 703cbaa601ff3fb554d1246c336ba727cc083ea0 (patch) | |
tree | 1d6c54f84f12ed6de8b299cb6b5976c504e40550 /drivers/cpufreq/amd_freq_sensitivity.c | |
parent | Merge tag 'pm-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm (diff) | |
download | linux-dev-703cbaa601ff3fb554d1246c336ba727cc083ea0.tar.xz linux-dev-703cbaa601ff3fb554d1246c336ba727cc083ea0.zip |
cpufreq: Skip cpufreq resume if it's not suspended
cpufreq_resume can be called even without preceding cpufreq_suspend.
This can happen in following scenario:
suspend_devices_and_enter
--> dpm_suspend_start
--> dpm_prepare
--> device_prepare : this function errors out
--> dpm_suspend: this is skipped due to dpm_prepare failure
this means cpufreq_suspend is skipped over
--> goto Recover_platform, due to previous error
--> goto Resume_devices
--> dpm_resume_end
--> dpm_resume
--> cpufreq_resume
In case schedutil is used as frequency governor, cpufreq_resume will
eventually call sugov_start, which does following:
memset(sg_cpu, 0, sizeof(*sg_cpu));
....
This effectively erases function pointer for frequency update, causing
crash later on. The function pointer would have been set correctly if
subsequent cpufreq_add_update_util_hook runs successfully, but that
function returns earlier because cpufreq_suspend was not called:
if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
return;
The fix is to check cpufreq_suspended first, if it's false, that means
cpufreq_suspend was not called in the first place, so do not resume
cpufreq.
Signed-off-by: Bo Yan <byan@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Dropped printing a message ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq/amd_freq_sensitivity.c')
0 files changed, 0 insertions, 0 deletions