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

[Takashi Iwai]

At Fri, 6 Jan 2006 04:24:22 +0000,
Pavel Machek wrote:
> 
> 
> > > > 1.) most sound cards have more than two states. (once again latency over
> > > > power savings trade offs)
> > > 
> > > What is the latency in typical "most sound card" case?
> > 
> > ACPI requires within 100ms for D1 and D2.  D3 can be longer.
> 
> Spec is useless here. 1usec is <100msec. Do you know any
> soundcard that takes >10msec from D3?

In the case of D3, the driver needs to initialize fully, and a latency
longer than 10ms may easily happen espeically with HZ=100.

Most of codec chips have powersave modes (disable converters and
amps), so having a "powersave" state makes sense, not only "on" and 
"suspend".


Takashi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/