Re: [PATCH RFC] PM / Runtime: Rework the "runtime idle" helper routine

[Aaron Lu <aaron.lu@intel.com>]

On 05/30/2013 06:18 AM, Rafael J. Wysocki wrote:
> On Wednesday, May 29, 2013 10:51:11 AM Alan Stern wrote:
>> On Wed, 29 May 2013, Rafael J. Wysocki wrote:
>>
>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>
>>> The "runtime idle" helper routine, rpm_idle(), currently ignores
>>> return values from .runtime_idle() callbacks executed by it.
>>>
>>> However, it turns out that many subsystems use the generic idle
>>> callback routine pm_generic_runtime_idle() which checks the return
>>> value of the driver's callback and executes pm_runtime_suspend() for
>>> the device unless that value is different from 0.  If that logic is
>>> moved to rpm_idle() instead, pm_generic_runtime_idle() can be dropped
>>> and its users will not need any .runtime_idle() callbacks any more.
>>
>> Since you're making this change, wouldn't it be a good idea to adopt
>> Mika's original suggestion and turn on the RPM_AUTO bit in rpmflags
>> when the use_autosuspend flag is set?
> 
> I'm not actually sure.  It can be done, but I'd prefer to do that as a separate
> change in any case.

For SCSI idle callback, that would be a welcome change, where instead of
calling pm_runtime_autosuspend and then return -EBUSY, it can be changed
to simply return 0 after mark_last_busy.

Thanks,
Aaron