From: Jon M. Taylor <taylorj@ecs.csus.edu>
  To  : ggi-develop@eskimo.com
  Date: Wed, 29 Jul 1998 13:20:15 -0700 (PDT)

Re: I've seen the stars too... [Re: kgicon, etc]

On Wed, 29 Jul 1998, Martin Eli Erhardsen wrote:

> Rodolphe Ortalo wrote:
> > 
> > Geert Uytterhoeven wrote:
> > >FYI: clgenfb (the Cirrus Logic driver for Amiga m68k and APUS) is in the vger
> > >tree... Add some PCI probing and it should work.
> > 
> > Hmmm. Geert, I've got a running kgi driver for nearly a year now...
> > Furthermore, I guess you are speaking of the 542x chipset series from
> > Cirrus Logic.
> > (BTW: the kgi driver from Martin should work on these chipsets too, provided
> > you remove the VGA IO region claim.)
> 
> I have just patched my 542x driver to work with kgicon, and commited to
> CVS.
> 
> My only problem with kgicon is that scrolling is REALLY SLOW.
> I could almost read the lines as they scrolled down the screen when
> doing
> a cat of a text file on my P133. 
> The normal textmode console is over 100 times faster.
> 
> How is it possible to write a scroller which is so slow.
> Does it copy the whole screen in the framebuffer every time.

	Yes, it reads the existing data out of the video memory and
rewrites it |-<.  This is because I turned off YWRAP, which at one point
was causing corrupted consoles on VT switches.  That problem may have been
fixed, I will try reenabling it and see what happens. 
 
> Most hardware supports setting the start adress of the display, which
> really
> would speed up the scrolling. 

	The YPAN setting of fbcon does that, IIRC.  I never tried it.

Jon

---
'Cloning and the reprogramming of DNA is the first serious step in 
becoming one with God.'
	- Scientist G. Richard Seed