I just made a pre-2.1.81 available on ftp.kernel.org.
This fixes the known problems of 2.1.80, and also makes the interrupt
routing by default look like it always used to look - everything goes
through the traditional external 8259A-compatible logic.
The code to handle IO-APIC interrupt routing is still there, but as no
interrupts are actually marked as io-apic interrupts you don't see it in
action yet. The advantage of this is that people who want to work on this
have a base that contains all the logic, and that we only need to figure
out how to reliably make all the IRQ routing decisions.

                Linus

This release should fix a few networking problems, and the NFS client is
hopefully fairly stable even under the kinds of loads we have here at
Transmeta.

The 2.1.80 release also contains some initial ARM support, and contains
Ingo Molnar's better SMP interrupt handling.

NOTE NOTE NOTE! The new SMP interrupt handling is currently not very good
at autodetection. This can be a real problem, and _before_ booting the
2.1.80 kernel as compiled for SMP you should probably try to figure out a
possible IRQ override line by doing:

        echo -n pirq=; echo `scanpci -f | grep T_L | cut -c56-` | sed 's/ /,/g'
which for me gives
        pirq=0x00,0x09,0x0b

Then, after doing the above, boot into 2.1.80 and see if it finds your PCI
interrupt lines correctly. If it does, everything is fine. If it doesn't,
you need to boot with the pirq setting that you determined earlier, by
giving the kernel the pirq data at the bootup command line or by using the
LILO "append=" feature (or similar features in other bootloaders).
We'll certainly have to make the autodetection work reliably, but in the
meantime the command-line approach at least gives us a way to test the
more fundamental impacts of better interrupt handling.

                Linus