Hi Rui,
> -----Original Message-----
> From: Zhang, Rui
> Sent: Friday, September 21, 2012 1:37 PM
> To: R, Durgadoss
> Cc: lenb@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; eduardo.valentin@xxxxxx
> Subject: Re: [PATCHv4 07/15] Thermal: Add a policy sysfs attribute
>
> On 二, 2012-09-18 at 11:04 +0530, Durgadoss R wrote:
> > This patch adds a policy sysfs attribute to a thermal zone.
> > This attribute denotes the throttling governor used for the
> > zone. This is a RW attribute.
> >
> > Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx>
> > ---
> > drivers/thermal/thermal_sys.c | 42
> ++++++++++++++++++++++++++++++++++++++---
> > 1 file changed, 39 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> > index a67c6c0..0948a60 100644
> > --- a/drivers/thermal/thermal_sys.c
> > +++ b/drivers/thermal/thermal_sys.c
> > @@ -454,10 +454,41 @@ passive_show(struct device *dev, struct
> device_attribute *attr,
> > return sprintf(buf, "%d\n", tz->forced_passive);
> > }
> >
> > +static ssize_t
> > +policy_store(struct device *dev, struct device_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + int ret = -EINVAL;
> > + struct thermal_zone_device *tz = to_thermal_zone(dev);
> > + struct thermal_governor *gov;
> > +
> > + mutex_lock(&thermal_governor_lock);
> > +
> > + gov = __find_governor(buf);
> > + if (!gov)
> > + goto exit;
> > +
> > + tz->governor = gov;
> > + ret = count;
> > +
> > +exit:
> > + mutex_unlock(&thermal_governor_lock);
> > + return ret;
> > +}
> > +
> > +static ssize_t
> > +policy_show(struct device *dev, struct device_attribute *devattr, char
> *buf)
> > +{
> > + struct thermal_zone_device *tz = to_thermal_zone(dev);
> > +
> > + return sprintf(buf, "%s\n", tz->governor->name);
> > +}
> > +
>
> we should introduce an API for platform thermal drivers to switch their
> policy.
> say they may want to switch to "userspace" to disable the kernel thermal
> control.
> and policy_store should invoke that function directly.
Yes, makes sense, we can introduce an EXPORT_SYMBOL API.
Thanks,
Durga
> BTW, IMO, deactiving all the thermal_instances and updating the cooling
> devices when a thermal zone switches to "userspace" governor is
> reasonable.
>
> thanks,
> rui
> > static DEVICE_ATTR(type, 0444, type_show, NULL);
> > static DEVICE_ATTR(temp, 0444, temp_show, NULL);
> > static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
> > static DEVICE_ATTR(passive, S_IRUGO | S_IWUSR, passive_show,
> passive_store);
> > +static DEVICE_ATTR(policy, S_IRUGO | S_IWUSR, policy_show,
> policy_store);
> >
> > /* sys I/F for cooling device */
> > #define to_cooling_device(_dev) \
> > @@ -1512,10 +1543,14 @@ struct thermal_zone_device
> *thermal_zone_device_register(const char *type,
> > passive = 1;
> > }
> >
> > - if (!passive)
> > - result = device_create_file(&tz->device,
> > - &dev_attr_passive);
> > + if (!passive) {
> > + result = device_create_file(&tz->device, &dev_attr_passive);
> > + if (result)
> > + goto unregister;
> > + }
> >
> > + /* Create policy attribute */
> > + result = device_create_file(&tz->device, &dev_attr_policy);
> > if (result)
> > goto unregister;
> >
> > @@ -1591,6 +1626,7 @@ void thermal_zone_device_unregister(struct
> thermal_zone_device *tz)
> > device_remove_file(&tz->device, &dev_attr_temp);
> > if (tz->ops->get_mode)
> > device_remove_file(&tz->device, &dev_attr_mode);
> > + device_remove_file(&tz->device, &dev_attr_policy);
> > remove_trip_attrs(tz);
> > tz->governor = NULL;
> >
>
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