Comment 60 for bug 397096

I also had the "ata ... frozen" symptom on system with AMD SB700/SB800 controler
with 2.6.26, 2.6.30 and 2.6.32. Comparing on similar systems, it seems (could be)
that it occurs more often with distinct hard drives or under distinct circumstances (?).

You may want to try some of following (step by step) to narrow down possible causes:

- disable SATA link speed to 1.5 Gbps
- (some of these) kernel command line parameters: hpet=disable highres=off nohz=off nohdparm
- disable services accessing drives: smartd, hddtemp, ...?
- change scheduler to deadline (echo 'deadline' >/sys/Block/sdx/queue/scheduler)

then test:

- test with RAID0 array over the drives
- test with RAID1 array over the drives
- test parallel access to single drives
- test if vibrations have an influence (?)

and of course

- test the hardware extensively (memtest86+ version 4.x, winxp with prime95 and bonnie++ in parallel (http://www.ziborski.net/wartung/bonnie++_win32.zip) (give lower priority to prime95), etc.)

then

- try new kernel
- read libata FAQ for further ideas

good luck ;)