On Wed, 9 Feb 2011, Stephan wrote:
probably. But this doesn't mean we can't enable tagged queuing now. At last for FC it should just work.The Linux driver also sais TQ is enabled on the SAS drives. As I said, the adapter doesn´t like that for now. Maybe some queue size parameters have to be tuned.
This might be the "adapt->adapt_max_periph = maxq" setting in mtp_netbsd.c, if maxq is > 256. The tagging done in the scsipi layer can only deal with 256 tags. I'm not sure how that would affect the mpt(4) driver. I did some work to get ciss(4) to do tagged queueing, and as best I could understand tagged queuing and the ciss driver, it looks like the ciss driver uses it's own tag and is not limited to 256. You could try setting adapt->adapt_max_periph to max(maxq, 256).
Another possibility is that maxq might be incorrectly calculated, but I have no understanding of that part of the mpt driver. I've been curious as to what the actual value of maxq is.
-- Michael L. Hitch mhitch%montana.edu@localhost Computer Consultant Information Technology Center Montana State University Bozeman, MT USA