Date: Mon, 29 Jun 1998 11:38:06 +0200 (MET DST) From: Josef Belkovics <belkovic@albert.osu.cz> To: freebsd-hackers@FreeBSD.ORG Subject: Re: BROKEN_KEYBOARD_RESET Message-ID: <Pine.BSF.3.95q.980629113722.1110A-100000@albert.osu.cz>
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> > My home pc (Cyrix 486DX4) does not a CPU reset via the keyboard controller > > or via invltbl() (/sys/i386/i386/vm_machdep.c). Is somebody able to say me > > patch which will reset through bios. Or in some other way. (Don't write - > > throw it out.) > > Write your own, if it matters that much to you. Look at how the VM86 > stuff calls the BIOS, find a suitable BIOS vector, and try it. > And if you manage to do it, please contribute the code! When I was a > FreeBSD newbie, I was stuck with such a motherboard. I switched to > FreeBSD from Linux, and I could reboot it with "reboot=bios" in Linux. > A friend of mine, and more experienced FreeBSD hacker, made a valiant > effort to port the code, but we never did get it to work. I've ditched > that motherboard (and the next one), but enough people still ask about > this problem that I would like to be able to point to a fix. > Does it have a PCI or EISA bus? There are PCI and EISA resets... Only ISA bus. > I would recommend disassembling the keyboard portion of the BIOS to > see what it's doing so you can duplicate it... Keyboard comes from xt (and has switch for xt/at). Probably its controller does not know about 'cpu reset' command. And 'cyrix 486dx4' certainly does not understand idea in invltbl(). I will try in asembler only following: a) i change cpu mode from protected to 'normal' b) i change appropriate segment registers c) i change appropriate bios constant to enable warm post d) i will call appropritae bios function (int 19h ?) Code will be on place of invltbl() in vm_machdep.c. This is only cca 10 instructions. Maybe it would try more experienced FreeBSD hacker. (Good example I saw in /sys/boot/biosboot. (I did hier quick hack to change vga palette register for white and green - the change in ?.h file for syscons.c left _white_ cursor - terrible.)) Josef Belkovics To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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