* Iru Cai mytbk920423@gmail.com [150330 18:24]:
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?
The same VGA OPROM binary is used for a whole set of different chipsets. However, the PCI header specification does not have a way to express that. The main system firmware has to know that, for a 0x0126 device it has to look for the 0x0106 OPROM. Hence coreboot has a mapping function for most newer (Intel) chipsets.
Stefan