For the record:

Jonas Petersson wrote:
> Owen Martin wrote:
>  > This looks like a timeout during a read command:
>  >
>  > ata3.00: cmd c8/00:08:90:3c:59
>  >
>  > Read dma of 8 blocks from 0x903c59
>  >
>  > Next time it happens, see if it is the same LBA. Since the drive came
>  > back after the bus reset makes me think it was probably in error
>  > recovery for an extended amount of time.
> 
> Sounds like a good idea. However, I had the drive swapped yesterday and 
> have now reinstalled on a (seemingly) identical one which so far seems 
> to be free from these messages. Hence, I keep my fingers crossed that 
> this was indeed a hw error.
 > [...]

I've now stressed the new disk for almost a week and seen no indication 
at all to the previous error. Everything else is the same as before - I 
even installed from the very same DVD. My conclusion is therefore that I 
really had a disk that was broken in a way that normal tests will not 
detect.

Hence, my tip to anyone having a similar experience: Don't blame the 
driver, nor the motherboard/chipset - just replace the drive. It would 
of course be even nicer if the error message could spell this out 
somewhat clearer too, but I guess the "I/O error" in the middle is a 
fair hint in retrospect.

			Best / Jonas