[coreboot] Serengeti VGA

Marc Jones Marc.Jones at amd.com
Mon Oct 20 22:26:03 CEST 2008


Myles Watson wrote:
> 
> 
> On Mon, Oct 20, 2008 at 1:48 PM, Marc Jones <Marc.Jones at amd.com 
> <mailto:Marc.Jones at amd.com>> wrote:
> 
>     Myles Watson wrote:
> 
>         I've been trying to make the configuration spaces match between
>         v2 and v3.
>         The biggest difference left is the disabled/hidden devices which
>         are not
>         hidden in v3.
> 
>         Any chance that's causing the problem?
> 
>         I've also been trying to figure out where the legacy IO space
>         (e.g. 0x3d4)
>         gets routed to the card.  Does this happen automatically because
>         the VGA bit
>         is set in the bridge?
> 
>     Yes, The vga bit on the subtractive bridge routes the graphics io.
> 
>     How did you work around the vm86 problem? Did the graphics command
>     register get re-enabled?
> 
> 
> I made the interrupts self contained, with no output.  The VGA ROM 
> initialization returns, but there is no output to the screen.  At least 
> the screen turns black on an int10 now, though.
> 
> The only differences between the PCI configuration registers now is that 
> v3 has a little larger space for VGA and SERR is set.

Ok, That should be fine. Black usually means all FF in the vga memory. 
Check A000-BFFFF are getting to the controller. VGA enable in the bridge 
control register (3e) and VGA pallet snoop in the command register (04) 
should be set in the bridge.

Marc


-- 
Marc Jones
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com
http://www.amd.com/embeddedprocessors





More information about the coreboot mailing list