[syslinux] Problem with Syslinux 2.07 and APM on SMP system

[Terry Barnaby]

Hi Josef,

We have two different dual processor servers here, one
is the new Supermicro 6023P-i server and one is based on an old
Supermicro P4DC6 Motherboard. Both fail in the same way.
The first worked Ok with Redhat 7.3 but not RedHat 9.
So I do not suspect the BIOS ....

I believe the kernel code changed between that in RedHat 7.3 and RedHat 9
with respect to the APM setup code checking on CPU number ....
The new kernel code taht fails is (BUG is called):

	/* 2002/08/01 - WT
	 * This is to avoid random crashes at boot time during initialization
	 * on SMP systems in case of "apm=power-off" mode. Seen on ASUS A7M266D.
	 * Some bioses don't like being called from CPU != 0.
	 * Method suggested by Ingo Molnar.
	 */
	if (cpu_number_map(smp_processor_id()) != 0) {
		current->cpus_allowed = 1;
		schedule();
		if (unlikely(cpu_number_map(smp_processor_id()) != 0))
			BUG();
	}

I will try Lilo and see what that does.

Cheers


Terry

Josef Siemes wrote:
> Hi,
> 
> Terry Barnaby <terry at beam.ltd.uk> schrieb am 07.01.04 15:12:09:
> 
>>The system boots fine using the standard Grub boot loader which loads
>>exactly the same kernel and initial RAM disk and APM works fine when
>>booted using Grub.
> 
> 
> Hmm. Grub does many things to the system (and I think it does way too much for the
> purpose it's needed for ...), and I AFAIK it also fiddles around with APM. 
> Maybe it 'fixes' your bios to behave more sane to the kernel.
> 
> Did you try lilo? It's similar to syslinux that it doesn't do too much to the
> system, and definitely doesn't touch APM either.
> 
> 
>>So there must be some difference between the way syslinux (pxe and iso)
>>boots Linux and Grub boots Linux that causes the failier.
>>
>>The code in the Linux kernal that prints the error message is attempting
>>to make sure the kernel is running on processor 0 as there are problems
>>with some BIOSes when other CPU's attempt to access the APM BIOS functions.
>>Could syslinux (pxe and iso) be booting using CPU 1 rather than CPU 0 ?
> 
> 
> Not that I know. AFAIK the BIOS (and that's what syslinux uses) runs on CPU 0,
> so there should be no problem with that.
> 
> Since it seems to be a bios issue you could try to upgrade the bios to the latest 
> version, if you didn't do that already. Since vitrually all installation CD's use syslinux
> (isolinux or syslinux itself) this should have happened to more people.
> 
> hpa, any comments?
> 
> Regards,
> 
> Josef
> 
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-- 
Dr Terry Barnaby                     BEAM Ltd
Phone: +44 1454 324512               Northavon Business Center, Dean Rd
Fax:   +44 1454 313172               Yate, Bristol, BS37 5NH, UK
Email: terry at beam.ltd.uk             Web: www.beam.ltd.uk
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