Re: sysfs and power management

Alan Cox
2010-10-27T12:43:11Z

> I started to wonder if it makes sense to enhance sysfs so that it
> optionally prodives open / close call backs. Internally sysfs has
> some bookkeeping about the refcount but this is not visible to the
> driver. Of course majority of the sysfs users doesn't need that at all
> and for them this is just overhead.

I think we need it. There doesn't need to be much overhead however as
there is no need (or sense) in providing per sysfs node open/close
hooks.

The pm layer also lacks a clean race-free way to actually ascertain
when the device was last kicked out of pm saving.