What's the right value for idle= (was: Re: [linux-pm] regression on P-II SMP)

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Sunday 21 February 2010, Guennadi Liakhovetski wrote:
> Hi
> 
> my 2xP-II@400MHz locks up with 2.6.32(.X) unless I specify "idle=*" on the 
> kernel command-line, where "*" is one of "poll," "mwait," "halt," and only 
> "nomwait" indeed locks it up. Last kernel known to work was 2.6.25. So, it 
> doesn't bother me all that much - I have a way to boot it, but maybe 
> someone would be interested to fix this (this system already has a few 
> quirks on the kernel command line, so, one more doesn't really hurt;)). 
> What interests me more - which of those shall I be using? From 
> Documentation/kernel-parameters.txt it looks like "mwait" should be best 
> for me? Or should I be using "halt?" "Poll" does indeed fry CPUs - raises 
> sys temperatures to 50 / 60 degrees C. Power-saving is not that much of a 
> concern for me - I only run that system occasionally, but it shouldn't 
> produce more heat than it must;) And since this system does have a broken 
> ACPI (Compaq AP400), I wouldn't try to be too smart with it.

I guess "mwait" is the right one, but let's try to ask experts.

Rafael