[coreboot] [patch] sb/via/k8t890: add vga textmode code for k8m890 chrome igp.

Luc Verhaegen libv at skynet.be
Mon Jul 27 16:06:45 CEST 2009

On Sun, Jul 26, 2009 at 02:21:34PM -0400, Kevin O'Connor wrote:
> On Thu, Jul 23, 2009 at 02:20:53PM +0200, Luc Verhaegen wrote:
> > Add initialisation for the VIA Chrome 9 IGP on the k8m890 through native code
> > and through the general vga infrastructure i committed a month or two ago.
> > Add videoram_size option for k8m890 and the Asus M2V-MX SE.
> > 
> > Now the Asus M2V-MX SE will magically come up with a working standard VGA
> > 80x25 textmode.
> Hi Luc,
> With your code, will the SeaBIOS vgabios (make out/vgabios.bin) run on
> the board?
> -Kevin

No; a general VGA bios is a broken concept to begin with.

What you should know is that VGA is _not_ a standard, and one should 
never, ever try to change the mode without more detailed hw knowledge.
It is only a standard through the int10 and vbe interfaces, where the 
manufacturers vga bios does all the vga and hw specific stuff for you.

What such a general bios should do is find out, one way or another, what 
mode has been set and how to stuff things into the framebuffer.

In this case: mode 3h: 80x25 with 8x16 fonts, with the framebuffer 
living at 0xB8000 and with vga standard cursor and fb offset handling.

So a general int10 bios should find this out and then claim to only 
support this and absolutely nothing else.

Everything else requires a whole bunch of hw specific code, and while 
you could spend the rest of your days porting graphics drivers from fb 
or X to this code, i think there are much better ways to spend ones 

Luc Verhaegen.

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