On ðÎÄ, 2001-12-17 at 06:34, Dave Jones wrote:
> On 16 Dec 2001, Borsenkow Andrej wrote:
>
> > I thought once about run-time detection - if BIOS reports that Idle does
> > not slow down CPU try Idle call once and compare jiffies (probably
> > repeat several times to be sure). Is it sensible?
>
> A far simpler way would be to add DMI blacklist entries for the BIOSes
> that don't do this, although this assumes the problem machine has a DMI
> compliant BIOS.
>
Well, the following three-liners (+ comments) seems to do it. It checks
if clock was advanced after return from APM Idle - if not we assume BIOS
did not halt CPU and do it ourselves. The addidional condition &&
!current->need_resched is for the case when BIOS did halt CPU and
non-clock interrupt happened that waked up somebody else. But may be I
am just plain paranoid. The code has no impact for "BIOS slows CPU"
case.
It works here for broken BIOS. I appreciate if people with good BIOS
test it.
-andrej
This archive was generated by hypermail 2b29 : Sun Dec 23 2001 - 21:00:16 EST