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

From: Richard Harman
Date: Sun Dec 30 2007 - 16:37:17 EST




Eduard-Gabriel Munteanu wrote:
On Sun, 30 Dec 2007 15:57:59 -0500
Richard Harman <richard@xxxxxxxxxxxxxxxxx> wrote:

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?

These two patches are not related in any way, they address two
different problems. My patch enables dynticks (and those messages don't
show up anymore), but it doesn't prevent your computer from locking up
as you said before.


The C1E patch, which permits the lapic to function *does* make my system stable. My previous method of testing (using USB peripherals) and checking /proc/interrupts for ERRor interrupts so far hasn't caused the system to lock up.

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