Re: [PATCH] x86-64: Disable local APIC timer use on AMD systems with C1E

[Ingo Molnar <mingo@elte.hu>]

* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> On Tuesday, 25 September 2007 22:55, Thomas Gleixner wrote:
> > On Tue, 2007-09-25 at 22:55 +0200, Rafael J. Wysocki wrote:
> > > I have reworked the patch a bit so that it applies on top of 2.6.23-rc8-mm1
> > > and compiles (my version is attached).
> > > 
> > > With this patch applied, the kernel boots correctly on the nx6325.
> > 
> > I know. It's basically enforced "noapictimer". 
> > 
> > But this still does not explain why your nasty box booted current
> > mainline with "apicmaintimer" on the kernel command line.
> 
> Now it doesn't do that any more.
> 
> As I wrote in the other thread, I think that _sometimes_ the CPU 
> doesn't enter the C1E state (or how it's called) and then the box 
> boots and works.

Can you see any correlation between being on AC or on battery and this 
bug occuring? Sometimes the BIOS might even do C states depending on 
whether the box was booted up on AC or on battery. (and sometimes the 
kernel calibrates things differently when booting up on battery [lower 
speed] - so this can have an effect too.)

	Ingo