Re: [patch] pm: fix runtime powermanagement's /sys interface

Patrick Mochel
2006-01-05T21:43:33Z

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On Wed, 4 Jan 2006, Alan Stern wrote:

> On Wed, 4 Jan 2006, Pavel Machek wrote:
>
> > > As I mentioned in the thread (currently happening, BTW) on the linux-pm
> > > list, what you want to do is accept a string that reflects an actual state
> > > that the device supports. For PCI devices that support low-power states,
> > > this would be "D1", "D2", "D3", etc. For USB devices, which only support
> > > an "on" and "suspended" state, the values that this patch parses would
> > > actually work.
> >
> > We want _common_ values, anyway. So, we do not want "D0", "D1", "D2",
> > "D3hot" in PCI cases. We probably want "on", "D1", "D2", "suspend",
> > and I'm not sure about those "D1" and "D2" parts. Userspace should not
> > have to know about details, it will mostly use "on"/"suspend" anyway.
>
> It would be good to make the details available so that they are there when
> needed. For instance, we might export "D0", "on", "D1", "D2", "D3", and
> "suspend", treating "on" as a synonym for "D0" and "suspend" as a synonym
> for "D3".

Do it in userspace; the kernel doesn't need to know about "on" or
"suspend". It should just validate and forward requests to enter specific
states.

Thanks,

Patrick