Date: Sun, 31 Dec 1995 15:25:46 +1100 (EST) From: David Dawes <dawes@rf900.physics.usyd.edu.au> To: smpatel@wam.umd.edu (Sujal Patel) Cc: jkh@time.cdrom.com, hackers@freebsd.org Subject: Re: /dev/io Message-ID: <199512310425.PAA16666@rf900.physics.usyd.edu.au> In-Reply-To: <Pine.BSF.3.91.951230231022.242A-100000@sl-046.sl.cybercomm.net> from "Sujal Patel" at Dec 30, 95 11:18:14 pm
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>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
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