From owner-freebsd-current Sun Jul 30 09:04:10 1995 Return-Path: current-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.11/8.6.6) id JAA13632 for current-outgoing; Sun, 30 Jul 1995 09:04:10 -0700 Received: from localhost.cdrom.com (localhost.cdrom.com [127.0.0.1]) by freefall.cdrom.com (8.6.11/8.6.6) with SMTP id JAA13623 ; Sun, 30 Jul 1995 09:04:06 -0700 Message-Id: <199507301604.JAA13623@freefall.cdrom.com> X-Authentication-Warning: freefall.cdrom.com: Host localhost.cdrom.com didn't use HELO protocol To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) cc: terry@cs.weber.edu, freebsd-current@freebsd.org, babb@freebsd.org Subject: Re: Update on my aic driver problems In-reply-to: Your message of "Sun, 30 Jul 95 17:34:33 +0200." <199507301534.RAA15394@uriah.heep.sax.de> Date: Sun, 30 Jul 1995 09:04:06 -0700 From: "Justin T. Gibbs" Sender: current-owner@freebsd.org Precedence: bulk >As Justin T. Gibbs wrote: >> >> >> The 6260 doesn't support scatter/gather, I believe. > >> >Hmm, well. Scatter/gather is a required feature for FreeBSD, ain't >> >it? >> >> No, its not. What you'll have to do is allocate a 64k contiguous >> staging buffer and do the transaction from there. Since scatter/gather >> is handled at the controller driver layer, the rest of the SCSI system >> makes no assumptions about it use... it just happens that most transactions >> are to buffers that are not physically contiguous, so if you use DMA, >> you must have the staging buffer. It should be possible to get it to >> work, but the performance won't be that great. > >Oops. The aic driver doesn't use DMA (it's in the TODO list at the >beginning of the file), so i'm not sure now: is this difference a >problem at all, or will i have to look elsewhere? It doesn't look like it does S/G either. I would think there are other differences in the chips then. > >Is there any doc available on the Adaptec chips? You can get them from the Adaptec Technical Documents department, but I don't know if they ship overseas. >-- >cheers, J"org > >joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ >Never trust an operating system you don't have sources for. ;-) -- Justin T. Gibbs =========================================== Software Developer - Walnut Creek CDROM FreeBSD: Turning PCs into workstations ===========================================