From owner-freebsd-hackers Tue Feb 18 01:28:07 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id BAA20000 for hackers-outgoing; Tue, 18 Feb 1997 01:28:07 -0800 (PST) Received: from root.com (implode.root.com [198.145.90.17]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id BAA19932 for ; Tue, 18 Feb 1997 01:28:00 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by root.com (8.8.5/8.6.5) with SMTP id BAA04915; Tue, 18 Feb 1997 01:29:09 -0800 (PST) Message-Id: <199702180929.BAA04915@root.com> X-Authentication-Warning: implode.root.com: localhost [127.0.0.1] didn't use HELO protocol To: Jason Thorpe cc: Christoph Kukulies , freebsd-hackers@freefall.freebsd.org Subject: Re: ccd and bounce buffers In-reply-to: Your message of "Mon, 17 Feb 1997 22:29:15 PST." <199702180629.WAA18272@lestat.nas.nasa.gov> From: David Greenman Reply-To: dg@root.com Date: Tue, 18 Feb 1997 01:29:09 -0800 Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk >[ note, this reply is directed more at whomever integrated the ccd > into freebsd, and/or has hacked on it in freebsd since then... ] > >On Mon, 17 Feb 1997 17:13:52 +0100 (MET) > Christoph Kukulies wrote: > > > Is it definite that ccd doesn't work for ISA (be it SCSI or IDE) > > due to bounce buffers being required? > >So, maybe I'm missing how things work in the FreeBSD world, but what >on earth does bounce buffers have to do with the ccd? The ccd is >a layered driver, which knows nothing about the underlying component >(or, at least, that's how it's _supposed_ to work, and is how it works >in NetBSD). > >Really, any dependency on bounce buffers out side of specific scsi >controller drivers is just plain broken. There is no dependency that I know of in FreeBSD. Bounce buffers are handled in the generic SCSI layer (via a machine-independant callout), and shouldn't be affected by ccd. I don't know where this rumor got started... -DG David Greenman Core-team/Principal Architect, The FreeBSD Project