Framebuffer or standard VGA ?

Peter Stuge stuge-linuxbios at
Wed Sep 11 04:17:01 CEST 2002

On Wed, Sep 11, 2002 at 08:55:21AM +0100, Antony Stone wrote:
> 1. there's a standard way for the motherboard Bios to initialise _any_ 
> graphics card, so it can initialise a new one it's never heard of before (and 
> presumably LinuxBios could do the same), or:

This is the case.  The way you reset a VGA card is to far call the real mode
address 0xc000:3.  This is what the system BIOS does pretty early on, before
saying anything to anyone looking at the screen.  Try starting debug.exe in
MS-DOS and enter
a 100
call c000:3
<blank line>

> Is there a flaw somewhere in my reasoning ?

Unfortunately, yes.
The problem is that video BIOSes run in real mode and tend to rely on legacy
system BIOS services.  These _can_ be rewritten but noone on this list is
very interested in doing so because it is a LOT of work that might never be
worthwhile anyway.  On the other hand, if it DOES get written it might also
be used for booting other, legacy, operating systems like MS-DOS or maybe
older Windows systems, both of these cases have been mentioned on the list,
but I do not believe either has very high priority.

Why need for textmode?  Why not just use the framebuffer?
Try playing with the old package SVGATextMode too.


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