From owner-freebsd-hackers Thu Apr 16 13:30:23 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id NAA23276 for freebsd-hackers-outgoing; Thu, 16 Apr 1998 13:30:23 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dingo.cdrom.com (dingo.cdrom.com [204.216.28.145]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id UAA23228 for ; Thu, 16 Apr 1998 20:30:14 GMT (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost [127.0.0.1]) by dingo.cdrom.com (8.8.8/8.8.5) with ESMTP id NAA01011; Thu, 16 Apr 1998 13:26:18 -0700 (PDT) Message-Id: <199804162026.NAA01011@dingo.cdrom.com> X-Mailer: exmh version 2.0zeta 7/24/97 To: Bernie Doehner cc: Mike Smith , hackers@FreeBSD.ORG, buaas@wireless.net, bad@wireless.net Subject: Re: Documentation of 2.2.5-RELEASE and 3.0 memory protection? In-reply-to: Your message of "Thu, 16 Apr 1998 16:22:40 EDT." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 16 Apr 1998 13:26:17 -0700 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > If you want to access memory on an expansion card in the ISA "hole", > > you need to memory-map it into your process. You need a cooperative > > driver for this - syscons allows you to memory-map video memory, and > > AFAIR it's not too picky about the offset you specify. > > But I don't see that being done in practice (or I wasn't able to wind my > way through the kernel sources - probably more likely)... I compared the > if_ed driver (some cards use shared memory, but in the ISA hole of > A0000-100000), to the Digiboard driver (which I thought uses shared > memory, but BELOW A0000). I don't understand you here - drivers are *inside* the kernel, and behave completely differently to user-mode programs. > The Digiboard driver pmap_mapdev's the address, but if_ed does NOT.. > > Our shared memory is in the ISA hole and we currently do not pmap_mapdev. > > buaas@wireless.net has also written another driver (for Dianatel > switch) which lived in monochrome memory, and he also didn't mmap and it > seemed it worked ok. Are you writing a driver, or a user-mode program? This is a critical difference. -- \\ 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