Re: add lowpower_idle sysctl

From: Ross Dickson
Date: Thu Mar 18 2004 - 02:49:39 EST


<snip>
> OK, so why not give us:
>
> #define IDLE_HALT 0
> #define IDLE_POLL 1
> #define IDLE_SUPER_LOW_POWER_HALT 2
>
> and so forth (are there any others?).

#define IDLE_C1HALT ?

I created another one for Athlon Nforce2 to prevent lockups in apic mode.
It is proving more useful than I thought.
It has also been used on SIS740 to prevent same problem.
I know such a workaround should not be required but it works well.

It modifies C1 state idle behaviour by being a little more intelligent about
when it is worthwhile to do into disconnect and has a crude but effective
delay in case of back to back disconnect reconnect cycles.
Recent post.
http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-03/4278.html
Patch is here.
http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-02/6520.html

Currently it is kernel arg activated by "idle=C1halt".

>
> Set some system-wide integer via a sysctl and let the particular
> architecture decide how best to implement the currently-selected idle mode?

A lockup detector on Athlon systems could conceivably invoke above idle state
after a manual reboot as not all systems of the same chipset have the problem.

Ross.

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