[coreboot] Error executing VGA ROM with coreboot

[Peter Stuge]

mansoor at iwavesystems.com wrote:
> Why coreboot can't run a VGA ROM which seabios can?
> What is the big difference while executing VGA ROM in coreboot and
> seabios?

Joe already mentioned it, but there is a big different in the amount
and quality of legacy BIOS interrupt services available at VGA ROM
run time depending on if it is run by coreboot, or by SeaBIOS.

coreboot doesn't want to have any BIOS services, while SeaBIOS
strives to be a fully featured BIOS.


> Real mode stub @00000500: 422 bytes
> Calling Option ROM...
> oprom: INT# 0x8e41a854
> oprom: eax: 8a000885 ebx: 0e21e039 ecx: 00028101 edx: 2989b606
> oprom: ebp: 58000a58 esp: c0010004 edi: c668404c esi: c2650304
> oprom:  ip: e6b0      cs: 8831   flags: 00002900
> Unexpected Exception: 6 @ 10:f6fdd07d - Halting
> Code: 0 eflags: 00010012
> eax: 00007776 ebx: 00008831 ecx: 0010ef73 edx: 001059b1
> edi: c0010004 esi: 8e41a854 ebp: 00002900 esp: 0000774a

8831:eb60 doesn't look like a place where the VGA ROM should be
executing.

Joe's suggestion to trace what is actually going on in the VGA ROM is
really good. You can use YABEL, or you can use SerialICE together
with QEMU. YABEL might be faster than SerialICE though.


//Peter