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authorVince Hsu <vinceh@nvidia.com>2014-11-10 14:14:50 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-11-11 23:04:28 +0100
commit619c144c84bd240487204e91dff88247cde68d92 (patch)
tree6f3961527611970a9ff3b0138ed67ab200d14a3e /drivers/cpufreq
parent8197bb1bffbee6a7678d20b4c1e77940cdaa8640 (diff)
downloadop-kernel-dev-619c144c84bd240487204e91dff88247cde68d92.zip
op-kernel-dev-619c144c84bd240487204e91dff88247cde68d92.tar.gz
cpufreq: respect the min/max settings from user space
When the user space tries to set scaling_(max|min)_freq through sysfs, the cpufreq_set_policy() asks other driver's opinions for the max/min frequencies. Some device drivers, like Tegra CPU EDP which is not upstreamed yet though, may constrain the CPU maximum frequency dynamically because of board design. So if the user space access happens and some driver is capping the cpu frequency at the same time, the user_policy->(max|min) is overridden by the capped value, and that's not expected by the user space. And if the user space is not invoked again, the CPU will always be capped by the user_policy->(max|min) even no drivers limit the CPU frequency any more. This patch preserves the user specified min/max settings, so that every time the cpufreq policy is updated, the new max/min can be re-evaluated correctly based on the user's expection and the present device drivers' status. Signed-off-by: Vince Hsu <vinceh@nvidia.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 644b54e..0721ab3 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -535,7 +535,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
static ssize_t store_##file_name \
(struct cpufreq_policy *policy, const char *buf, size_t count) \
{ \
- int ret; \
+ int ret, temp; \
struct cpufreq_policy new_policy; \
\
ret = cpufreq_get_policy(&new_policy, policy->cpu); \
@@ -546,8 +546,10 @@ static ssize_t store_##file_name \
if (ret != 1) \
return -EINVAL; \
\
+ temp = new_policy.object; \
ret = cpufreq_set_policy(policy, &new_policy); \
- policy->user_policy.object = policy->object; \
+ if (!ret) \
+ policy->user_policy.object = temp; \
\
return ret ? ret : count; \
}
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