From owner-freebsd-hardware Sat Oct 31 10:53:21 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA00593 for freebsd-hardware-outgoing; Sat, 31 Oct 1998 10:53:21 -0800 (PST) (envelope-from owner-freebsd-hardware@FreeBSD.ORG) Received: from austin.polstra.com (austin.polstra.com [206.213.73.10]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA00587 for ; Sat, 31 Oct 1998 10:53:19 -0800 (PST) (envelope-from jdp@austin.polstra.com) Received: from austin.polstra.com (jdp@localhost) by austin.polstra.com (8.9.1/8.9.1) with ESMTP id KAA22693 for ; Sat, 31 Oct 1998 10:53:15 -0800 (PST) (envelope-from jdp) Message-Id: <199810311853.KAA22693@austin.polstra.com> To: hardware@FreeBSD.ORG Subject: Mixing 8- and 16-bit shared memory ISA cards Date: Sat, 31 Oct 1998 10:53:15 -0800 From: John Polstra Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I have a question for you old farts who still remember ISA. I'm trying to turn an old 486 box into an ethernet <-> frame relay router. It has a 16-bit SMC 8013 card with shared memory, and also an 8-bit ET Inc. card with shared memory. I have this vague recollection that you can run into problems with a mix like that in an ISA machine. In particular, I seem to recall something along the lines that each 128K chunk of the address space (a0000-bffff, c0000-dffff, e0000-fffff) has to do either all 8-bit accesses or all 16-bit accesses, but not a mix of the two. Is that correct? Is it true for FreeBSD systems, or was it just an MS-DOS thing? Is such a mix guaranteed not to work, or does it just sometimes not work? Also, is the address chunk e0000-effff generally available on ISA 486 systems (non-IBM)? I know it used to be reserved for the Basic ROM on ancient IBM machines. Finally, what about the range a0000-bffff that is generally used by video cards? The docs for my card (an old 1 MB Orchid ProDesigner ISA card) say that it uses that whole range. But I am only using it in text mode with the syscons driver. Will it still take up that whole address range in that case, or will part of the address space be free for other cards? John -- John Polstra jdp@polstra.com John D. Polstra & Co., Inc. Seattle, Washington USA "Nobody ever went broke underestimating the taste of the American public." -- H. L. Mencken To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message