This is my port of the Diamond clock setting program written by
Frank Klemm (pfk@rz.uni-jena.de).  Originally it would not run
under linux. 

This program has _NO_ proprietary information from Diamond in it.
You are free to use it and tell your friends.  You won't be
fined, sued, or forced to wear an albatross around your neck. 

I have included the binary and sources in this package. The
binary has been compiled with GCC 2.2.2d7 and the 4.1 libraries. 
If you have different libraries you might do well to recompile. 
A makefile is included.  

The program needs to be owned by root (chown root freq), and the
setuid bit must be set too (chown a+sx freq).  The execute flag
should be set as well.  The safest thing to do with this program
is set the second clock ONLY.  To use this program with X you
need to set the clock line in your Xconfig as follows:  

    Clocks 25 28 xx         ; where xx is some dummy value

The dummy value is only used as a placeholder.  X doesn't use the
value at all.  The only thing that you have to do is make sure
that the resolution that needs to have the clock set has this
dummy value as its clock value.  This insures that X selects the
third (clock 2) clock for the dot clock.  

The Diamond card has three clocks (0 - 2) all three clocks seem
to be programmable.  The first two (0 and 1) are rather weird to
monkey with.  They are preset to 25.1 and 28.2 MHz respectively
on power up or cold boot.  They are not reset by a warm boot. 
They are only reset on a cold boot or power up.  The third one
(2) seems to be the best one to play with.  I basically ignore
the first two clocks and pretend that they are not programmable.

Also, note that this is a one way street.  Once the clock is set
you cannot read back the values you wrote.  However, there are
other programs out there (clocks.exe under DOS in particular) 
that can derive the dot clock frequency.  I have clocks.exe 
and have run freq under MS-DOG and clocks accurately reports 
the frequency that I previously set.

What I have been able to do is start X to the 640x480 resolution. 
Open up an Xterm window and do: 

    freq xxxxx y      ;xxxxx being the dot clock freq I want
                       in kHz
                      ;y being the clock to set (0 - 2)
                       typically 2

This sends the screen into fits.  At this point I then do
Ctrl-Alt-keypad +.  This switches to the next resolution in my
Xconfig. The screen then syncs up real nice. :) You can also run
freq from the text prompt and then start X with the same results. 
Also, by repeatedly switching resolutions with C-A-+ the next
time you get to 640x480 the screen will be normal again.  X knows
to use clock 0, and FREQ forces the use of the clock being set,
thus, the screen confusion. 

Enjoy this program, I know I do.  Oh, and one more thing.  Hey
Diamond it was only a matter of time! 

Ray Balister
balister@cebaf.gov