[SeaBIOS] Status of SeaBIOS VGA bios.

Kevin O'Connor kevin at koconnor.net
Wed Oct 26 02:26:33 CEST 2011


On Wed, Oct 26, 2011 at 12:16:32AM +0100, Julian Pidancet wrote:
> Hi,
> 
> I stumbled across the vgasrc directory in the SeaBIOS git tree which
> seem to contain the source of a VGA Bios. I havn't found any related
> documentation nor announcements regarding this, and there is no
> Makefiles or scripts to build it. That's why I'm enquiring here about
> the status of this project.

You can build the vgabios by running:

make out/vgabios.bin

There was a brief note on the vga code some time back:

http://www.coreboot.org/pipermail/coreboot/2009-May/047775.html

> I've got several questions:
> - What is the general status of this project ?

I started converting the VGA bios from the "lgpl vga bios" project (
http://savannah.nongnu.org/projects/vgabios/ ) a couple of years ago.
I converted the base code, but did not have time to convert the "VBE"
or the "cirrus" code.

There was also an effort a few years back to get the code running on
real hardware that had some success.

> - Is this code intended to be executed in a 32bit environment by
> transitionning from 16bit to 32bit mode for each BIOS call as SeaBIOS
> already does ?

The current seabios vgabios code runs exclusively in 16bit mode.
(Note, SeaBIOS also has some calls handled entirely in 16bit mode as
well.)

> - Is this code able to run independantly from SeaBIOS ?

It should - but I've never tested it that way.

> - How can I build the sources ?

make out/vgabios.bin

> I am currently working on a emulated graphic adapter for Xen and I
> would like to implement a VBE driver for it. This VGA BIOS seems to be
> a good base for that kind of work. Would that be possible ?

It should work.  Ideally, someone would complete the port of the "lgpl
vgabios".  This involves translating the remaining 16bit assembler to
C code and then doing lots of testing on the result.

-Kevin



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