Adding non standard VGA modes

[Bernhard Guillon]

Hi all,
I want to ask if it is possible to add non standard VGA modes like 800x480 
to seabios vgabios implementation. I want to be able to use it for qemu. 
After looking at the code I am puzzeled about the "random numbers" 
e.g. [1]. 
Can you hint me to any documentation or books I can read to understand 
what they are doing?

best regards,
Bernhard

1 http://code.coreboot.org/p/seabios/source/tree/master/vgasrc/vgatables.c

[Kevin O'Connor]

On Fri, Jul 15, 2011 at 01:42:43PM +0200, Bernhard Guillon wrote:
> Hi all,
> I want to ask if it is possible to add non standard VGA modes like
> 800x480 to seabios vgabios implementation. I want to be able to use
> it for qemu. After looking at the code I am puzzeled about the
> "random numbers" e.g. [1]. Can you hint me to any documentation or
> books I can read to understand what they are doing?

The code is a port of the GPL'd vgabios:
http://www.nongnu.org/vgabios/

I ported only the basic VGA functionality - non standard modes are in
the "vesa" and "cirrus" branches of the code.  It would be nice to
port that over as well.

The "magic" numbers are the register settings of the VGA adapter for
various modes.  Here's a link I have that has assorted info:

http://www.osdever.net/FreeVGA/home.htm

-Kevin

[Bernhard Guillon]

On Sun, 17 Jul 2011, Kevin O'Connor wrote:
> On Fri, Jul 15, 2011 at 01:42:43PM +0200, Bernhard Guillon wrote:
> > Hi all,
> > I want to ask if it is possible to add non standard VGA modes like
> > 800x480 to seabios vgabios implementation. I want to be able to use
> > it for qemu. After looking at the code I am puzzeled about the
> > "random numbers" e.g. [1]. Can you hint me to any documentation or
> > books I can read to understand what they are doing?
>
> The code is a port of the GPL'd vgabios:
> http://www.nongnu.org/vgabios/
>
> I ported only the basic VGA functionality - non standard modes are in
> the "vesa" and "cirrus" branches of the code.  It would be nice to
> port that over as well.
>
> The "magic" numbers are the register settings of the VGA adapter for
> various modes.  Here's a link I have that has assorted info:
>
> http://www.osdever.net/FreeVGA/home.htm

Thank you for the information :)

I will read the code and the docu and try to add some other modes.

best regards,
Bernhard