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

Dominik Brodowski
2006-01-05T22:13:34Z

On Thu, Jan 05, 2006 at 10:55:29PM +0100, Pavel Machek wrote:
> > I have a firewire controller in a desktop system, and a ATI Radeon in a
> > T42 that support D1 and D2..
>
> Ok, now we have a concrete example. So Radeon supports D1. But putting
> radeon into D1 means you probably want to blank your screen and turn
> the backlight off; that takes *long* time anyway. So you can simply
> put your radeon into D3 and save a bit more power.

Using your logic, you never want to put your CPU into C2 power-saving state
instead of C3 or C4. Which is ridiculous. There are technical reasons why
you want to put devices into different power-saving states. E.g. wakeup
latency, ability to receive wakeup signals, snooping and so on.

In addition, your patch breaks pcmcia / pcmciautils which already uses
numbers (which I already had to change from "3" to "2" before...).

Dominik