io_apic & timer_ack fix

[Jon Grimm <jgrimm2@us.ibm.com>]

Hmmm....

I see that the following patch got pulled in by Andrew:
http://linux.bkbits.net:8080/linux-2.5/diffs/arch/i386/kernel/io_apic.c@1.85?nav=index.html|src/|src/arch|src/arch/i386|src/arch/i386/kernel|hist/arch/i386/kernel/io_apic.c

The patch had a couple bugs:
http://seclists.org/lists/linux-kernel/2004/Mar/4152.html

But the patch was pulled out entirely by Linus:
http://linux.bkbits.net:8080/linux-2.5/diffs/arch/i386/kernel/io_apic.c@1.88?nav=index.html|src/|src/arch|src/arch/i386|src/arch/i386/kernel|hist/arch/i386/kernel/io_apic.c

Was it determined that the fix was bogus? damaging?  fixable?

I ask as I see behavior identical for which this patch seems to have 
been originally carved up for (buggy SMM BIOS at fault, but this was a 
workaround in the OS). 

http://marc.theaimsgroup.com/?l=linux-kernel&m=101604672921823&w=2
http://www.ussg.iu.edu/hypermail/linux/kernel/0203.2/0698.html

Its a fair answer to force the BIOS vendor to fix, but in the meantime, 
I'm trying to figure out how safe/unsafe the workaround patch is ?   
I've ran on it overnight (with the semi-colon's fixed) and it hasn't 
exhibited the troubling behavior (where timer interrupts seem stuck or 
in some cases just extremely slow.... and the 8259 IMR is mucked up when 
Linux isn't even touching anymore).

NMI interrupts are comming in at furious rate, but I see a patch in 
Andrew's tree to handle that.

Best Regards,
Jon Grimm