
STB Powergraph VL-24 Utilities
------------------------------

This archive contains source code and makefile for two useful programs if
you own a STB Powergraph VL-24 video card from STB corporation.  Under
Linux, the XS3 server does not know how to initialize the clock synthesizer
on the video card.  The utility 'setclk' in this archive can be used to
initialize the various clocks of the video card.  I think it can also be
used for the non-local bus version of this card - the X-24.

These sources wre ported from example programs posted by STB's Tom Wheeler
on the corporate BBS.  No copyright notices were present in the code.  The
original file was called 'clockio.zip'.  The BBS number is (214) 437-9615

The clock chip used is the ICD 2061 or 2061A.  I do not have a copy of the 
data sheets for this chip nor any application notes.  So, I do not know the
theory behind these utilities.


Building the Utilities
----------------------

Just uncompress and un-tar the archive into any old directory.  Type 'make'
and two programs should be created:

	setclk	- Set a clock to a specified frequency
	gencode - Generate a 21 bit clock chip initialization code.

Install them in any available space.  I put mine in /usr/local/bin.


Running the Utilities
---------------------

Since the 'setclk' utility must be run before the X server may be started,
the /etc/rc.local file is good place to run it from.  The syntax is:

	setclk <clock num> <frequency>

The clock number is anything from 0 to 15 (I think).  The frequency should
be a floating point frequency useable for the video mode you expect to
run from this clock.  For example, I run 1024x768 at 70 Hz refresh.  I use
the third clock (clock num = 2) and a frequency of 75.0 MHz.  So, the
command line is:

	setclk 2 75.0

Please use the 'modegen1.sc' spreadsheet to calculate the proper modedb
line values for your monitor's operating envelope.  Do not hold me responsible
for blowing up your cheep or discrete freq monitor!

Good Luck and let me hear about success stories.  This code will hopefully 
make it into the XFree2.0 X server so that the VL-24 and other accelerated
chip sets can be supported.


Enjoy.

Bob Moody
rlm@hpenv2.lad.lmsc.lockheed.com  OR p657371@shrike.austin.lockheed.com



Several graphic cards using the icd2061a and a s3-928 graphic processor
had problems with this program due to the fact that they didn't like
the outw calls. I changed these calls to two outb calls and it worked.

Helmut Geyer
geyer@kalliope.iwr.uni-heidelberg.de



