[coreboot] Question on VGA BIOS extraction

[Timothy Pearson]

On 03/30/2015 11:24 AM, Iru Cai wrote:
> Hi,
>
> I'm trying to build Coreboot for ThinkPad X220. I first backup the
> vendor BIOS, then use UEFITool to extract a VBIOS. The romheader program
> detects the ROM's PCI data structure and reports the device id is
> 8086:0106, but the VGA controller's device id is 8086:0126. I extracted
> the video ROM from a running X220 memory and use romheader to test it,
> the result is still 8086:0106. How could this happen?
>
> Iru
>

Some PCI devices can change their device ID based on a configuration 
register or two (I know the XGI Volari can do this for instance).  It is 
possible that the proprietary BIOS changes the ID for some reason.

-- 
Timothy Pearson
Raptor Engineering
+1 (415) 727-8645
http://www.raptorengineeringinc.com