CAM/SIIS CAM_CMD_TIMEOUT hangs

[Alexander Motin]

James R. Van Artsdalen wrote:
> I have problems with I/O hanging due to CAM/SIIS not handling the
> CAM_CMD_TIMEOUT error.
> Hangs happen every few hundred GB to every few TB.
> The disks are behind SATA port multipliers.
> 
> This command un-hangs the drive and lets things run again:
> 
> # camcontrol reset all
> 
> I assume this is sending a soft reset to the disk drive but haven't
> checked yet.
> 
> Is there a way xpt_done() or such might notice a CAM_CMD_TIMEOUT and
> inject a "soft reset" request at the head of the I/O queue (to run
> before the timed-out command retries)?

Try my latest patch against HEAD:
http://people.freebsd.org/~mav/cam-ata.20091028.patch

It does hard reset after timeout, and what is important, it
reinitializes PMP after reset, to re-enable it's ports back.

-- 
Alexander Motin