From owner-freebsd-hackers Sat Dec 30 20:27:21 1995 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id UAA05832 for hackers-outgoing; Sat, 30 Dec 1995 20:27:21 -0800 (PST) Received: from rf900.physics.usyd.edu.au (rf900.physics.usyd.edu.au [129.78.129.109]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id UAA05819 for ; Sat, 30 Dec 1995 20:27:01 -0800 (PST) Received: (from dawes@localhost) by rf900.physics.usyd.edu.au (8.6.11/8.6.9) id PAA16666; Sun, 31 Dec 1995 15:25:46 +1100 From: David Dawes Message-Id: <199512310425.PAA16666@rf900.physics.usyd.edu.au> Subject: Re: /dev/io To: smpatel@wam.umd.edu (Sujal Patel) Date: Sun, 31 Dec 1995 15:25:46 +1100 (EST) Cc: jkh@time.cdrom.com, hackers@freebsd.org In-Reply-To: from "Sujal Patel" at Dec 30, 95 11:18:14 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-hackers@freebsd.org Precedence: bulk >On Sun, 31 Dec 1995, David Dawes wrote: > >> >I think a few X servers would definitely break of /dev/io went away >> >suddently, but I also see no reason why the other interface couldn't >> >be implemented in parallel with a change-over at some point in the >> >future. >> >> For what it's worth, the XFree86 servers get I/O permission by using >> the KDENABIO ioctl in the console driver rather than by opening /dev/io. > >I wasn't even aware that this existed, but looking at the Xserver source >it seems like BSDI, Linux, FreeBSD, and NetBSD all have it (but only >Free/NetBSD use it for Xserver IO permission). The KDENABIO ioctl originates in SYSV, although in SYSV it is used to enable ports set in an IO permission bitmap. Most X servers need ports beyond the 0-0x3ff usually covered by such a bitmap. Also there is a performance penalty in using the bitmap. I don't know what the XInside server does to enable I/O permission. David