From owner-freebsd-hackers Sun Jan 31 06:56:17 1999 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id GAA07351 for freebsd-hackers-outgoing; Sun, 31 Jan 1999 06:56:17 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dingo.cdrom.com (castles216.castles.com [208.214.165.216]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id GAA07346 for ; Sun, 31 Jan 1999 06:56:15 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost [127.0.0.1]) by dingo.cdrom.com (8.9.1/8.8.8) with ESMTP id GAA06506; Sun, 31 Jan 1999 06:52:26 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Message-Id: <199901311452.GAA06506@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: wschlanger@usa.net, hackers@FreeBSD.ORG Subject: Re: ISA limmitation of 16MB for DMA [wschlanger@usa.net: ] In-reply-to: Your message of "Sun, 31 Jan 1999 05:21:09 +0100." <19990131052109.A1053@panke.de.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 31 Jan 1999 06:52:25 -0800 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG FreeBSD uses the time-honoured technique of "bounce buffering" - it maintains a pool of buffers in ISA-addressable space, and allocates them as required to back pending ISA busmaster transactions. This is handled transparently by the bus-space DMA code, which adds several levels of indirection to the issue. You may find the older kernels (2.2.x) technique which involved explicit cooperation by the driver easier to understand. > ----- Forwarded message from Willow Schlanger ----- > > Thanks. Would you happen to know where I can learn how FreeBSD gets > around the ISA limmitation of 16MB for DMA? Is there a source file I can > see that demonstrates this? > > Thanks in advance, > Willow Schlanger > > Wolfram Schneider wrote: > > > > On 1999-01-24 03:49:02 -0800, Willow Schlanger wrote: > > > Q: Hi. I'm a programmer and I'm interested in the kernel source code for > > > FreeBSD. I can't seem to find it anywhere - I've tried different FTPs > > > FreeBSD.org mentions, but I can never figure them out. I use DOS and > > > Windows 95/98 -- do I need some special program to get the assembly > > > language and C/++ sources? > > > > [cc: freebsd-questions] > > > > The FreeBSD kernel sources code is available at > > > > ftp://ftp.freebsd.org/pub/FreeBSD/FreeBSD-current/src/sys > > > > or > > http://www.freebsd.org/cgi/cvsweb.cgi/src/sys > > > > > > > > Can you help me? > > > > > > Thanks in advance, > > > Willow Schlanger > > > > -- > > Wolfram Schneider http://freebsd.org/~w/ > > ----- End forwarded message ----- > > -- > Wolfram Schneider http://freebsd.org/~w/ > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message