[coreboot] Integrated graphics controller on second bus?

Andrej Skirn andrejskirn at celestials.net
Tue Dec 29 06:10:47 CET 2009

Hiya again. I've gotten the CompuLab CM-iVCF board (Was: VIA EDEN ESP 
(C3) + Apollo CLE266(VT8623) + VT8237R + W83627HG) getting to start 
booting Windows XP (There was data at the address the northbridge code 
looks for SPD, but closer inspection revealed it was neither SPD nor 
EDID. I hard-coded the memory initialization, this also solved problem 
with the romcc compiled code not fitting into the bootblock).
Unfortunately, now I can't seem to get the VGA-BIOS/northbridge VGA 
adapter working. Biggest problem seems to be that the Unichrome device 
is on second PCI bus, and I can't find any documentation or example on 
how to configure CoreBoot to probe and activate devices on other buses. 
In lspci this shows up as device 01:00.0, but the devicemap parser 
doesn't accept the bus number. I have tried to place it hierachically 
under AGP Bridge on the first bus, but CoreBoot still parses it as 
00:00.0 and doesn't find the correct device. So how do I define a device 
on second PCI bus for CoreBoot?
I am also looking at the vgabios.c code in epia-m board, but notice that 
it has been disabled (ie. the device initialization functions no longer 
called). Is there some reason for this? The Wiki still talks about 
concatenating the VGA BIOS to the image, although the current way seems 
to be to include it in CBFS. Is there anywhere I can find more 
information about the best/preferred way to integrate VGA BIOS into 

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