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SubjectRe: Linux 2.2.6 IO-APIC <feature>
On Wed, 28 Apr 1999, Ingo Molnar wrote:

>
> On Tue, 27 Apr 1999, Richard B. Johnson wrote:
>
> > Hello IO-APIC/SMP gurus,
> >
> > I have finally upgraded all my CPUs to linux 2.2.6. They all work
> > except this one! This one refuses to use IRQ0 on both CPUs. The
> > kernel declares that the timer is not connected to the APIC. However,
> > Linux version 2.1.127 (the last version running on that machine)
> > found and used the timer without any problem!
> >
> > Perhaps there still needs to be some work done here?
> >
> > CPU0 CPU1
> > 0: 54716 0 XT-PIC timer
>
> i would not be worried too much about the timer interrupt. It only does
> timekeeping. even in 2.1.127 it was not 'perfect' IO-APIC interrupt, but a
> special 'ExtINT' interrupt, delivered to all CPUs. This proved to give
> problems on certain boxes. Moving timer-list handling from IRQ0 to the
> local per-CPU interrupt in 2.3 should solve this problem. (then IRQ0 will
> only be used for timekeeping) [the timer IRQ does not execute the timer
> lists, but it's the IRQ mostly likely to trigger timer_bh processing)
>
> if you want to experiment wether your system is able to distribute all
> ExtINT interrupts to all CPUs, just change setup_ExtINT_pin() in
> io_apic.c:
>
> - entry.dest.physical.physical_dest = boot_cpu_id;
> + entry.dest.physical.physical_dest = 0xff;
>
> -- mingo
>

Okay, Thanks, I will check it out.

Cheers,
Dick Johnson
***** FILE SYSTEM WAS MODIFIED *****
Penguin : Linux version 2.2.6 on an i686 machine (400.59 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.


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