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PM: Devfreq: fix userspace governor frequency bug

PATCH MyungJoo Ham 1 participant 1 message Jul 3, 2012

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MyungJoo Ham

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Quoted 10 lines

The frequency set by userspace governor may not the same as the final frequency. If this condition happens, then "cat set_freq" will return a wrong value which is inconsistant with the real frequency.

This patch updates data->user_frequency after calling of update_devfreq. use devfreq->revious_freq as the final user_frequency.

Signed-off-by Xiaoguang Chen <[email protected]>

No, this is not a bug.

---- quoting Documentation/ABI/testing/sysfs-class-devfreq ----

What:           /sys/class/devfreq/.../userspace/set_freq
Date:           September 2011
Contact:        MyungJoo Ham <[email protected]>

Description:
The /sys/class/devfreq/.../userspace/set_freq shows and sets the requested frequency for the devfreq object if userspace governor is in effect.
---- quote ended ----

set_freq shows the requested frequency, not the actual frequency value.

If you want to see the actual current frequency intended by devfreq, use "cur_freq".

Cheers!
MyungJoo

Quoted 19 lines
---
 drivers/devfreq/governor_userspace.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
drivers/devfreq/governor_userspace.c +1 -0
index 0681246..85ad80a 100644
@@ -59,6 +59,7 @@ static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
 	err = update_devfreq(devfreq);
 	if (err == 0)
 		err = count;
+	data->user_frequency = devfreq->previous_freq;
 	mutex_unlock(&devfreq->lock);
 	return err;
 }
Signature · 1 line
1.7.0.4

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