Re: [PATCH 0/3] MMC / PM: Make it possible to use PM QoS latency constraints

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Tuesday, March 06, 2012, Adrian Hunter wrote:
> On 04/03/12 02:01, Rafael J. Wysocki wrote:
> > Hi all,
> > 
> > The goal of this patchset is to allow user space to control the
> > responsiveness of the MMC stack related to runtime power management.
> 
> I wonder why this is build into mmc and not just a generic runtime pm
> facility. e.g.
> 
> 	/* Set maximum resume latency target to 100ms */
> 	pm_runtime_set_max_latency(dev, 100);

That actually is

 	dev_pm_qos_add_request(dev, req, 100);

where req is used as a handle for your request (it may be used, for
example, to remove the request or update it).

> And then runtime pm will create sysfs attributes etc

Well, there may be an interface for drivers analogous to
device_wakeup_enable()/device_wakeup_disable() allowing them
to add/remove a sysfs attribute for user space to control
a single PM QoS constraint.  That even sounds like a good idea. :-)

Thanks,
Rafael