On Tue, May 21, 2013 at 11:14:03PM -0700, Brian Buhrow wrote: > hello. Recently I've been working on some fixes for the mpt(4) > driver. In the process of getting those fixes working, I began thinking > about how hard it would be to get NCQ tag queueing working for NetBSD. In > the process of getting my head around what is involved, I find I have > questions. If someone wants to share what they know here or privately, > I'd be interested in reading. > > 1. I read a document that discussed ahcisata and its advantages over > traditional IDE mode. One of the advantages it touted was that ahcisata > would support NCQ tag queueing. Is it a requirement in order for NCQ > tag queueing to work that the interface card support it as well? For > example, the viaide(4) driver supports SATA controllers, but says nothing > about NCQ support or the potential for it.
Yeah, you need something with more than just wdc(4)/pciide(4)-style registers. ahcisata(4), siisata(4), and mvsata(4) would be capable of NCQ. > 2. Does anyone have any preliminary patches for NCQ support that the never > got into the system? The first issue is the ata(4) layer, which doesn't currently support multiple outstanding commands per drive. What little work I did on it I probably swept away, as nothing useful came of it last I tried. Jonathan Kollasch