Re: Legacy I/O ports and text mode

On Jul 25, 2005, at 9:39 PM, Michael Steil wrote:
>     outl((1 << 31) | (0<<16) | (0x1e<<11) | (0<<8) | 0x3c, 0xcf8);
>     outl(inl(0xcfc) | (1<<19), 0xcfc);
[...]
> The first two lines set bit 19 of register 0x3c of the AGP-to-PCI  
> bridge (0:1e.0), which enables AGP-PCI-passthrough of the legacy I/ 
> O ports and memory regions of VGA. In Linux, this bit is already  
> set for some reason.

P.S.: In case you wonder where I knew this from: The nForce chipset  
is based on the AMD-762 chipset, which is documented quite well. Look  
for 24462.pdf, page 145.

   Michael