Date: Mon, 28 Apr 1997 09:43:33 +0200 From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-hackers@FreeBSD.org Subject: Re: sysctl -A Message-ID: <19970428094333.SR56034@uriah.heep.sax.de> In-Reply-To: <199704271942.MAA09077@phaeton.artisoft.com>; from Terry Lambert on Apr 27, 1997 12:42:18 -0700 References: <19970427091019.YV06768@uriah.heep.sax.de> <199704271942.MAA09077@phaeton.artisoft.com>
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As Terry Lambert wrote: > > > My DEC Alpha runs at secure level 1, and X works fine. > > > > So now, look and tell us how they're doing it. > > They map the display memory with a kernel call. ...and don't have to do IO calls. Both is essentially impossible with the crappy PeeCee architecture. Determining the frame buffer location inside the video driver is possible only for dumb banked VGAs (which nobody is using for X11), or for PCI devices (which would still be quite some restriction right now). It's not that XFree86 seemed to be very happy about mmap'ing /dev/mem, but that's been the only viable alternative for quite some time. We should probably add the ability to mmap the frame buffer for PCI devices today, so XFree86 can use this API tomorrow. Still, this would either require a graphics card that can be completely handled with mmap'ed registers, or you stumble across the IO crap. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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