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Subject: Re: [REGRESSION from 2.6.23-rc8] (was: Re: 2.6.23-rc4-mm1 and
	-rc6-mm1: boot failure on HP nx6325, related to clockevents)
From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, Andi Kleen <ak@suse.de>,
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Date: Thu, 27 Sep 2007 00:35:01 +0200
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On Wed, 2007-09-26 at 15:22 -0700, Linus Torvalds wrote:
> 
> On Wed, 26 Sep 2007, Thomas Gleixner wrote:
> > > 
> > > 1) current Linus' tree doesn't boot with any command line (regression)
> > > 
> > > [  Linus, please revert commit e66485d747505e9d960b864fc6c37f8b2afafaf0
> 
> Reverted.
> 
> > OK, this explains 2) and 3). I just looked into the code and the logic
> > vs. noapictimer on SMP is completely broken.
> 
> ..and thanks for the explanation.
> 
> Thanks for finding it so quickly guys. Sounds like this will be fixed 
> properly in 2.6.24 with the x86 merge (which hopefully brings in the hrt 
> patch too)

It's even worse than I thought on the first check:

"noapictimer" on the command line of an SMP box prevents _ONLY_ the boot
CPU apic timer from being used. But the secondary CPU is still
unconditionally setting up the APIC timer and uses the non calibrated
variable calibration_result, which is of course 0, to setup the APIC
timer. Wreckage guaranteed.

	tglx