If it is an error in the drivers (e.g. software), why should it show up in a hardware test?
From what information I've got it looks like something was broken in the ata_piix kernel module between versions 2.6.28-9 and 2.6.28-11 and then subsequently fixed (it could also be an error somewhere else that triggers erroneous behaviour in the ata_piix driver).
If it is an error in the drivers (e.g. software), why should it show up in a hardware test?
From what information I've got it looks like something was broken in the ata_piix kernel module between versions 2.6.28-9 and 2.6.28-11 and then subsequently fixed (it could also be an error somewhere else that triggers erroneous behaviour in the ata_piix driver).