[coreboot] Black screen during SeaBIOS boot

[Taiidan at gmx.com]

On 12/17/2017 02:54 PM, Daniel K wrote:

> I assumed this meant I didn't need a vgabios.rom, am I right?
For the main AST 2050 video, or a PCI-e card that has an onboard Option 
ROM (all of them)
> Or should I be actually including a vgabios.rom for the on-board VGA even though I never plan on using it?
No you don't need it as coreboot supports text mode native init for AST 
2050.
> An even stranger question: should I be including a vgabios.rom for the PCIe VGA? This seems unlikely because factory BIOSes usually work with new video cards without needing to update the BIOS.
You simply need to select "Execute Option ROM's on PCI-e devices" and 
"Execute VGA Option ROM's" in menuconfig with the appropriate security 
settings - this will load it from the card and it is what the factory 
vendor BIOS does.

I am not sure how SeaBIOS interacts with those, but I know it should 
work with grub.
> Or is the issue that SeaBIOS doesn't work in text-mode-only?
> Maybe I'll give GRUB2 a try, that should work in text-mode-only right?
Both work text mode, the "graphics" you see in SeaBIOS is still text it 
is similar to an ncurses program.

I suggest trying GRUB with both those above options and the multiple 
video adapters option enabled, it is what I use. (FYI You can embed a 
grub.cfg that searches for and loads other grub.cfg's from your disks)

Also "CONFIG_ONBOARD_VGA_IS_PRIMARY" should be N if you wish to use your 
PCI-e video device to see the payload screens.