Re: ç­å¤: K8 northbridge f1 behaviour.

ron minnich rminnich at
Fri Jan 9 10:20:00 CET 2004

On 8 Jan 2004, Eric W. Biederman wrote:

> That is very weird.  Besides the card not working what test
> are you using to be certain you have failed?  Are you failing
> to read/write an I/O register.

on "normal" bios, i/o to 0x3cc produces data. On linuxbios, i/o to 0x3cc 
always comes back as 0xff. 

Here is my understanding of the tyan s2885 layout: cpu0, link2, goes to 
the 8131, which has a tunnel to 8111, which drives pci. 

Under our linuxbios + hack, c0.b is 0x33. c4.l is set for link2. So VGA 
i/o should in  my view go out link2. 

the 8111 is the pci connection. register 3e.b in 8111 is set to 0xf, which 
should pass vga i/o to the pci bus. 

the vga card, using Ollie's 'userio' program, does not respond to byte 
accesses to 0x3cc or 0x3d4. Under normal bios, all these register settings 
are the same and ... the card responds. 

> It occurs to me LinuxBIOS might be different enough in pci layout to
> confuse the option ROM on your card.

no, I don't think that's it.

> Plus I think there are some special bits of AGP initialization that
> we might not be doing.

even on pci it won't work.


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