On Sun, 24 Nov 1996 14:13:44 -0800 
 Greg Wohletz <greg@duke.CS.UNLV.EDU> wrote:

 > Oh, one more thing, we have 3 other servers using the same bus logic
 > controlers, but not using the ccd driver, these have been working hard for
 > several months without any hangs.  Seems like there is some strange
 > intereaction between the ccd and certain scsi disk drivers.

The only thing that the ccd does is fire off transfers to the underlying
component devices.  If the ccd is interleaved (striped), you may have
multiple outstanding transactions on a given controller.

However, the ccd does not know or care what kind of device the underlying
componet is.  If you're getting hangs when using the ccd on SCSI disks
on BusLogic controllers, I'd suspect a buglet in either the sd or bha
drivers (maybe something in an exceptional condition handler?).  Maybe
a race condition in the bha driver?  Maybe a missing splx()?

Or maybe buggy firmware on the specific BusLogic controller you had problems
with.  Or maybe a disk that didn't behave well with a BusLogic controller.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
NAS: M/S 258-6                                          Work: 415.604.0935
Moffett Field, CA 94035                                Pager: 415.428.6939