Supporting extension ROMs and beyond...
rminnich at lanl.gov
Mon Aug 11 19:04:01 CEST 2003
On Mon, 11 Aug 2003, YhLu wrote:
> I try to move the vgabios to freebios2 for 2880. I put the BIOS option rom
> to 0xfff8c000, ( the second 48k).
ah, well, we shouldn't really do that until we resolve the VGA bios
Looks, however, looke tehre is a bug ... Takeshi can perhaps address it
better than I.
I did look at our three options today: emulation, ADLO, and VGABIOS.
VGABIOS is almost 100% C save for the 32-16 trampoline code.
ADLO rombios.c is mostly assembly code with C wrappers around it.
Emulation is C.
Emulation is 256K
ADLO is 64K.
VGABIOS is much less, something like 16K last time I built it.
The functions that VGABIOS needs to finish up to have as complete support
as bringing up graphics as ADLO are not that many in number. Which makes
sense: what a VGA BIOS needs to do is diddle its own registers, so most
BISO functionality is not that useful for them.
ADLO will not find the option rom on a card and use it; VGABIOS will.
The most portable long-term way to go is emulation. I don't have room.
These are the issues I have seen so far.
More information about the coreboot