From: Andrew Apted <ajapted@netspace.net.au>
  To  : ggi-develop@eskimo.com
  Date: Sun, 5 Jul 1998 18:41:35 +1000

Re: kgicon difficulties |-< (and new tarballs |->)

Jon writes:

>  	Today did NOT go as smoothly as yesterday did.  I am having
>  problems getting 4bpp modes to work right.  The 4bpp routines in fbcon
>  have some major problems, it seems.  The foreground color is hardwired to
>  15, which I found and patched after much head-scratching, but there is
>  still a very strange problem with garbled fonts which I cannot for the
>  life of me track down.  

AFAIK (and that aint far), fbcon-cfb4.c is for "4 bit packed pixels"
which is like the code in lib/libggi/default/linear-4/*, whereas VGA 4
bit mode is a weird thing called "ModeX" and needs code like the stuff
in kgi/lib/libggi/IBM/*.

Also, is the 640x400x4bit mode banked ?  It must take up at least 128K,
but the window at A0000 is usually only 64K (again AFAIK, which aint
much).

>  	4bpp support is vital, for without it we cannot use VGA 640x400x4
>  which is the only graphics mode that is useable for text and that all VGA+
>  cards can set.

It's going to be tricky using that mode from userspace if it really is
banked.  KGI gets round this by mmap tricks -- pretend it is linear and
use the nopage handler to swap banks on-the-fly.  It'd be nice if fbcon
could allow this too [the VGER tree now has an mmap hook -- so it is
probably doable].

>  	The new tarballs are finally available!  Get 'em at:
>  
>  	http://gaia.ecs.csus.edu/~taylorj/kgicon.tar.gz and
>          http://gaia.ecs.csus.edu/~taylorj/kgicon-include.tar.gz

Great !  Now that I've got a lend of a VGA monitor, I'll be trying this
ASAP !

Cheers,
_____________________________________________  ____
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  Andrew Apted   <andrew@ggi-project.org>       \/