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

Scott E. Preece
2006-01-05T15:16:12Z

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My inclination would be to have the sysfs interface know generic terms,
with the implementation mapping them to device-specific terms. It ought
to be possible to build portable tools that don't have to know about
device-specific states and have the device interfaces (in sysfs) do the
necessary translation.

However, I also think there is value in having the sysfs interface
recognize the device-specific values as well, so that device-specific
tools can also be written (offering the option of taking advantage of
special capabilities of a particular device).

scott

| On St 04-01-06 17:06:09, 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".
|
| Why to make it this complex?
|
| I do not think there's any confusion possible. "on" always corresponds
| to "D0", and "suspend" is "D3". Anyone who knows what "D2" means,
| should know that, too...
| Pavel
| --
| Thanks, Sharp!
|
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scott preece
motorola mobile devices, il67, 1800 s. oak st., champaign, il 61820
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