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address@hidden: Bug#139774: GRUB hangs until A20 is not goofy :P]
From: |
Jason Thomas |
Subject: |
address@hidden: Bug#139774: GRUB hangs until A20 is not goofy :P] |
Date: |
Tue, 2 Apr 2002 09:04:16 +1000 |
User-agent: |
Mutt/1.3.27i |
okay more information from the bug reporter, is this a know problem, is
it fixed already?
Thanks.
----- Forwarded message from Zinx Verituse <address@hidden> -----
> Date: Sun, 24 Mar 2002 22:05:17 -0600
> From: Zinx Verituse <address@hidden>
> To: address@hidden
> Subject: Bug#139774: GRUB hangs until A20 is not goofy :P
>
> Well, it turns out this motherboard likes to disable the keyboard
> controller completely. Including the A20 gate.
>
> Porting the code from Linux would fix this, as it seems to have
> some code to cover all the cases, or at least all the ones that
> matter.
>
> For now, I've written my own gateA20 function that uses port 0x92..
> Apparently not all systems have this functionality, and some that do
> don't implement it fully (though I don't know if the problems will
> affect GRUB)
>
> Copying from Linux (which copies from SYSLINUX) would be the best,
> I think :)
>
> my gateA20:
>
> /*
> * gateA20(int linear)
> *
> * Gate address-line 20 for high memory.
> *
> * This routine will fail on some computers.
> */
>
> ENTRY(gateA20)
> pushl %eax
>
> inb $0x92, %al
> andb $0xfe, %al
> testb $2, %al
> jz goff
>
> cmpl $0, 0x8(%esp)
> jnz gret
>
> andb $0xfc, %al
> outb $0x92
> jmp gret
>
> goff:
> cmpl $0, 0x8(%esp)
> jz gret
>
> orb $2, %al
> outb $0x92
>
> gret:
> popl %eax
> ret
>
> --
> Zinx Verituse
>
----- End forwarded message -----
--
Jason Thomas Phone: +61 2 6257 7111
System Administrator - UID 0 Fax: +61 2 6257 7311
tSA Consulting Group Pty. Ltd. Mobile: 0418 29 66 81
1 Hall Street Lyneham ACT 2602 http://www.topic.com.au/
- address@hidden: Bug#139774: GRUB hangs until A20 is not goofy :P],
Jason Thomas <=