Re: [PATCH] Option to disable AMD C1E (allows dynticks to work)

Richard Harman
2007-12-30T21:02:42Z

Eduard-Gabriel Munteanu wrote:
> On Sun, 30 Dec 2007 03:49:21 +0200
>
> Note that this problem is only related to AMD64 multi-core laptops. As
> far as I can see, devs might not invest much coding effort into this
> and instead say "Go buy an Intel laptop!", as this really is a hardware
> quirk. And if Andi Kleen is correct, this is not just a laptop vendors'
> problem, but AMD itself doesn't offer support for higher C-states.
>

I think I may have a monkey wrench to throw into this, I finally got
around to testing the C1E patch, and the port80 patch. End result:
port80 patch has zero effect on this laptop, and the C1E patch makes it
stable.

AMD C1E patch 'force_amd_c1e' (disabling the workaround):

hpet0: at MMIO 0xfed00000, IRQs 2, 8, 31
hpet0: 3 32-bit timers, 25000000 Hz
Time: hpet clocksource has been installed.
Clockevents: could not switch to one-shot mode: lapic is not functional.
Could not switch to high resolution mode on CPU 0
Clockevents: could not switch to one-shot mode: lapic is not functional.
Could not switch to high resolution mode on CPU 1

And with the C1E workaround enabled, the kernel doesn't whine that the
lapic isn't functional.

Those were the kernel messages I was trying to paste in my earlier
message, saying that the lapic works. Do I have a DV6000 laptop that is
a strange beast all in itself?