I discovered this after running a custom kernel with support for ATA 
read verify command, when I encountered sector errors and saw them 
reported in syslog and on an ATA analyzer but when I tried to read the 
LBA registers I got zero... problem was this one liner, which applies to 
2.6.8-rc2 as well as 2.6.7, and I've also included a 2.4.26 version.

Thanks,
BR