Quoting Ingo Molnar [off-list ref]:
Subject: Re: [2/6] 2.6.21-rc2: known regressions


* Linus Torvalds [off-list ref] wrote:

quoted

quoted

3. When I switch to X (CTRL-ALT-F7), X hangs after drawing a couple of windows
   after waiting for some 10 min, I rebooted. no new messages showed 
   up in /var/log/messages

I think this is likely just more of the disk being buggered, but it 
could again be related to NO_HZ (people report time not advancing, and 
that would make any X timeout taking forever, and you'd see exactly 
your behaviour).

Michael - does your 'date' output advance after resume? If not then i'd 
say it's a NO_HZ related problem. If yes then i'd guess it's the SATA 
problem.

I'll test, but I have NO_HZ off for now.

-- 
MST