Re: [PATCH] PM: Devfreq: fix userspace governor frequency bug

Re: [PATCH] PM: Devfreq: fix userspace governor frequency bug

[MyungJoo Ham]

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> 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 <chenxg@marvell.com>

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 <myungjoo.ham@samsung.com>
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


> ---
>  drivers/devfreq/governor_userspace.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
> index 0681246..85ad80a 100644
> --- a/drivers/devfreq/governor_userspace.c
> +++ b/drivers/devfreq/governor_userspace.c
> @@ -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;
>  }
> -- 
> 1.7.0.4
> 
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[PATCH] PM: Devfreq: fix userspace governor frequency bug

[Xiaoguang Chen]

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 <chenxg@marvell.com>
---
 drivers/devfreq/governor_userspace.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
index 0681246..85ad80a 100644
--- a/drivers/devfreq/governor_userspace.c
+++ b/drivers/devfreq/governor_userspace.c
@@ -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;
 }
-- 
1.7.0.4