I get this all the time on my machine and I really have no idea why. I notice that this happens regardless if I am using Ubuntu | Debian | CentOS.

Anyone know how I can find out why this is happening and or what it means.

I'm doing some research on that issue (mainly in kernel and bug mailing lists) -- could you please post what kind of computer you are using (make/model, etc) as well as what your kernel version is, AND have a look through your /var/log/dmesg file after bootup, and post anything odd or erronious from there too? Any errors, APIC problems, IQR problems, etc?

Thanks.

Dell Optiplex GX 745

Intel Core 2 Duo E6300 CPU
Dell OEM Motherboard
2 GB DDR2 RAM
nVidia GeForce 7600GT
Dual Seagate S-ATA 250GB Hard drive

Running Ubuntu 7.04 using Linux Kernel 2.6.21

For the time being, try booting up with an extra option on the boot command line. The option is irqpoll and has been reported to work around this problem.
Add that either to the kernel voot line from your grub menu by using 'e' to get the boot line, or with lilo, if you use a password to boot, just hit return at the password prompt and add irqpoll to the kernel boot line, and go ahead and boot. You could also add it to the lilo.conf file as an append at the beginning.
I'm still reading, but let me know if that reduces or eliminates it.

Also, as I mentioned earlier, are ther any messages in dmesg, like this one about IRQ 233 or any about the ATA disks like this:

ATA: abnormal status 0xD8 on port 0xF807
ATA: abnormal status 0xD8 on port 0xF807
ATA: abnormal status 0xD8 on port 0xF807
ATA: abnormal status 0xD8 on port 0xF807

Do you get any of this?

If you're still working on it, check in your BIOS for several options:

Set 'plug & play BIOS' to 'Yes'
Check if you have an option in the disk section of the BIOS for '32 bit transfer mode' and if so, enable it (instead of 16 bit mode).

As with my last post, if this still is happening, add another kernel boot parameter: acpi=off