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Date: Fri, 1 Aug 2014 18:43:15 +0800
From: Fengguang Wu <fengguang.wu@intel.com>
To: Prarit Bhargava <prarit@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Aaron Lu <aaron.lu@intel.com>, LKML <linux-kernel@vger.kernel.org>
Subject: [BUG cpufreq] Invalid argument on writing to scaling_governor
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Hi Prarit,

I noticed that commit dbcbfe6aa0d61ae5e13cab43b30802482007c199 ("cpufreq: hold
policy->rwsem for duration of changing governors") will cause this problem:

root@nhm4 ~# echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor
-bash: echo: write error: Invalid argument

root@nhm4 ~# cat /sys/devices/system/cpu/cpu3/cpufreq/scaling_available_governors
conservative userspace powersave ondemand performance

Thanks,
Fengguang