APIC on AMD Athlon 2500+ Broken?

[Lennart Sorensen]

On Mon, Jul 05, 2004 at 08:49:45PM -0400, Tim Writer wrote:
> Agreed but knowing that a device or its driver is broken doesn't go very far
> towards solving the problem.  Enabling APIC is a viable workaround.

I wonder if it is a hardware problem, or just a driver problem (if it is
driver, I wonder if there is a fix).

> I'm sure many of us have.  I'm equally sure many of us have had problems with
> such a system.  In an ideal world, we'd all be running Linux on high quality,
> reasonably priced hardware.  Unfortunately, we don't live in an ideal world.
> The state of PC hardware is such that even if you take a great deal of care
> in picking your components (and I did), you can still run into problems.

I must have been lucky when picking hardware then.  For me it just
works.

> I'm not using their software RAID.  I'm using their on-board RAID controller
> as ide2 and ide3, that's all.

So it is simply another ide controller then.  No point calling it
onboard raid then.  I am surprised that doesn't just work, given I have
worked with many promise ide controllers without any problems (both with
and without apic).

> You seem to have completely missed the point of my post which was simply to
> illustrate that APIC _can_ be useful for single CPU systems.

Well it can if you have defective hardware/drivers that need help for
fixing the irq sharing problem which should never have existed.  on
multi cpu systems it is used to help router irqs to multiple cpus nicely
(wheere it makes sense).  It also introduces a bit more lag into the
handling of cpus than not using the APIC (which I suspect is why it
causes sound choppiness on under XP on this and similar boards).

If turning on the apic fixes it, well lucky for you.  The apic handling
has often been broken on many systems, so it often causes more grief
than it fixes.  I almost suspect Linux has turned it on on this machine
even though it is off in the Bios, although it's still working just
fine.  I seem to have interrupts higher than 15 so I suspect some apic
is enabled.

Lennart Sorensen
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