[LinuxBIOS] VGA (Tyan s2881)

[Ward Vandewege]

Hi all,

I'm trying to get VGA working on the Tyan s2881.

I've extracted a 32KB VGA rom image while running under the proprietary BIOS.
It looks all right: it starts with 55 AA, has ATI strings in it, and it stops
just before the next option rom starts with 55 AA.

I've enabled

#VGA Console
  default CONFIG_CONSOLE_VGA=1
  default CONFIG_PCI_ROM_RUN=1

in src/mainboard/tyan/s2881/Options.lb

I've modified the ROM_SIZE in targets/tyan/s2881/Config.lb:

option ROM_SIZE = 491520

I've appended the linuxbios rom to the vgabios, and burned that image.

It boots fine, but no VGA output.

I've verified the contents of the video memory after booting:

dd if=/dev/mem of=vga.bios bs=1 count=32768 skip=786432

The memory area is identical to the vga bios image I extracted.

I've attached the boot log. It sees the VGA device, and it says it copies the
ROM image to 0xc0000, all 0x8000 bytes of it.

I wonder about this halt_sys line:

...
copying VGA ROM Image from 0xfff80000 to 0xc0000, 0x8000 bytes
entering emulator
halt_sys: file
  /personal/projects/gnu/chimera/linuxbios/lbv2/rev-latest/LinuxBIOSv2/src/devices/emulator/x86emu/ops.c,
  line 4387
PCI: 01:04.0 init
...

I feel like I'm missing something pretty obvious here. Suggestions?

I also wonder why it's _always_ booting the fallback image. I have the same
payload for primary and fallback for now. Is this because there is 'dirty'
CMOS data?

Thanks,
Ward.