intel_pstate: Fix user input of min/max to legal policy region
authorChen Yu <yu.c.chen@intel.com>
Wed, 9 Sep 2015 10:27:31 +0000 (18:27 +0800)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Wed, 9 Sep 2015 20:55:23 +0000 (22:55 +0200)
commit43717aadd2bc87fb10fbf1cd815c1cbae9bb95b3
treea525f784c4a857f55c09d6dc8eee594ea042cffb
parent953ba9ff77f3d08635712eaeffb218d46889b58a
intel_pstate: Fix user input of min/max to legal policy region

In current code, max_perf_pct might be smaller than min_perf_pct
by improper user input:

$ grep . /sys/devices/system/cpu/intel_pstate/m*_perf_pct
/sys/devices/system/cpu/intel_pstate/max_perf_pct:100
/sys/devices/system/cpu/intel_pstate/min_perf_pct:100

$ echo 80 > /sys/devices/system/cpu/intel_pstate/max_perf_pct

$ grep . /sys/devices/system/cpu/intel_pstate/m*_perf_pct
/sys/devices/system/cpu/intel_pstate/max_perf_pct:80
/sys/devices/system/cpu/intel_pstate/min_perf_pct:100

Fix this problem by 2 steps:
 1. Normalize the user input to [min_policy, max_policy].
 2. Make sure max_perf_pct>=min_perf_pct, suggested by Seiichi Ikarashi.

Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Acked-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/cpufreq/intel_pstate.c