(sorry for screwing with the thread, I was not subscribed when I read the original post)
The patch seems to work just fine. It's been running for six hours now with varying amounts of load and no catastrophes has occurred so far.
Only things are these lines saying 'abnormal status' (which has been there all along). I assume the codes mean 'device not present' (which would be correct, at least in my case) or something similar, but I don't know for sure so I leave it to someone better informed to patch :)
(also, there is the 'Unknown device'-thing in my lspci, but that's neither related to libata nor is it a 'real' problem)
Using a Promise FastTrack S150 SX4
Relevant piece of my dmesg, lspci follows (just let me know if you need the rest)