Re: [PATCH] drivers: thermal: do not clobber cooling dev state from userspace

[Lina Iyer]

Adding Ram, so he can respond.
-- Lina

On Thu, Jul 26 2018 at 02:55 -0600, Zhang Rui wrote:
> On ä, 2018-05-07 at 11:55 -0600, Lina Iyer wrote:
> > From: Ram Chandrasekar <rkumbako@xxxxxxxxxxxxxx>
> >
> > Let userspace be another voter for cooling device state instead of
> > the
> > overriding authority. It is possible that the thermal governor may
> > find
> > a higher cooling state desirable than what is recommended by the
> > userspace. Separate out the current cooling device state from the
> > userspace request and aggregate the userspace request with the
> > governors' recommendation.
>
> hmmm, I don't understand this.
> If the governor does not work well, we should either improve the
> governor or use userspace governor instead.
> do you have any examples that the kernel governor chooses improper
> cooling state?
>
> thanks,
> rui
>
> > Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
> > ---
> > Âdrivers/thermal/thermal_core.cÂÂÂÂ| 1 +
> > Âdrivers/thermal/thermal_helpers.c | 2 +-
> > Âdrivers/thermal/thermal_sysfs.cÂÂÂ| 8 +++++++-
> > Âinclude/linux/thermal.hÂÂÂÂÂÂÂÂÂÂÂ| 1 +
> > Â4 files changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/thermal/thermal_core.c
> > b/drivers/thermal/thermal_core.c
> > index 589925ac0994..c2e13e122934 100644
> > --- a/drivers/thermal/thermal_core.c
> > +++ b/drivers/thermal/thermal_core.c
> > @@ -970,6 +970,7 @@ __thermal_cooling_device_register(struct
> > device_node *np,
> > Â	cdev->updated = false;
> > Â	cdev->device.class = &thermal_class;
> > Â	cdev->devdata = devdata;
> > +	cdev->sysfs_req = 0;
> > Â	thermal_cooling_device_setup_sysfs(cdev);
> > Â	dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
> > Â	result = device_register(&cdev->device);
> > diff --git a/drivers/thermal/thermal_helpers.c
> > b/drivers/thermal/thermal_helpers.c
> > index 2ba756af76b7..f550fdee0f9b 100644
> > --- a/drivers/thermal/thermal_helpers.c
> > +++ b/drivers/thermal/thermal_helpers.c
> > @@ -166,7 +166,7 @@ EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
> > Âvoid thermal_cdev_update(struct thermal_cooling_device *cdev)
> > Â{
> > Â	struct thermal_instance *instance;
> > -	unsigned long target = 0;
> > +	unsigned long target = cdev->sysfs_req;
> > Â
> > Â	mutex_lock(&cdev->lock);
> > Â	/* cooling device is updated*/
> > diff --git a/drivers/thermal/thermal_sysfs.c
> > b/drivers/thermal/thermal_sysfs.c
> > index 275ffee292bf..eddada715ad2 100644
> > --- a/drivers/thermal/thermal_sysfs.c
> > +++ b/drivers/thermal/thermal_sysfs.c
> > @@ -719,7 +719,13 @@ thermal_cooling_device_cur_state_store(struct
> > device *dev,
> > Â	result = cdev->ops->set_cur_state(cdev, state);
> > Â	if (result)
> > Â		return result;
> > -	thermal_cooling_device_stats_update(cdev, state);
> > +
> > +	cdev->sysfs_req = state;
> > +	mutex_lock(&cdev->lock);
> > +	cdev->updated = false;
> > +	mutex_unlock(&cdev->lock);
> > +	thermal_cdev_update(cdev);
> > +
> > Â	return count;
> > Â}
> > Â
> > diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> > index 5f4705f46c2f..7a133bd6ff86 100644
> > --- a/include/linux/thermal.h
> > +++ b/include/linux/thermal.h
> > @@ -139,6 +139,7 @@ struct thermal_cooling_device {
> > Â	struct mutex lock; /* protect thermal_instances list */
> > Â	struct list_head thermal_instances;
> > Â	struct list_head node;
> > +	unsigned long sysfs_req;
> > Â};
> > Â
> > Âstruct thermal_attr {