Just noticed that most of the mails I wrote on this thread were
apparently without linux-kernel cc'ed (dunno who removed the cc). So
I'll write a small summary - the problem is that hddtemp includes some
fragile code to check the sense info, and this commit:
http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=f38621b3109068adc8430bc2d170ccea59df4261
broke it. hddtemp expects 14, but it now sees 12. IMHO hddtemp is buggy
and should be fixed, the best option is simply to kill the sense checks
as I think they have little (if any) value. Patch below for that.
So the problem was never the SG_IO changes, the fact that somebody
noticed the same thing in bugzilla for a 2.6.19-rc6-mm kernel backs that
up.