[plug] changing refresh rate

[Cameron Patrick]

On Sat, Feb 08, 2003 at 03:11:05PM +0800, Ben Jensz wrote:
| Its a "Personal Desktop" installation type install of Red Hat 8.0.
| 
| These seem to be the parts of XF86Config related to the monitor and
| video card:
| 
| Section "Monitor"
|         Identifier   "Monitor0"
|         VendorName   "Monitor Vendor"
|         ModelName    "P90f"
|         HorizSync    30.0 - 110.0
|         VertRefresh  50.0 - 180.0
|         Option      "dpms"
| EndSection

The HorizSync is way higher than what my monitors can do, so I'm
guessing that's not your problem.  I'd imagine that XFree doesn't have a
built in Modeline for such a high resolution and high refresh rate.  The
simplest way to get one is from a CGI script like this one:

	http://koala.ilog.fr/cgi-bin/nph-colas-modelines

It will spit out a pile of Modelines which you can paste into the bottom
of the Monitor section of your XF86Config file.  It generates them for a
pile of different resolutions at once, essentially in 8-pixel increments
from some default resolution.  If you know you won't be using all of
those weird resolutions you can only copy in the ones that you need;
conversely, leaving in resolutions that you don't actually use won't
hurt anything.

I had to fiddle with the "relaxed timings" option at the bottom of the
page before my graphics card and monitor were satisfied with the
script's output, though - in particular, I needed to give it a negative
value (i.e. make the timings tighter) before the graphics card driver
would accept the mode lines.

Another thing to try would be to feed a vastly higher "maximum bandwidth" than
the default.  Both graphics cards in my machine claim to support
12-350MHz, and one of them is quite old, so presumably you should have
no worries with at least that high a value, and you will probably need
it to get the best out of your monitor :)

CP.

(PS. Entering your monitor specs and a max dot clock of 350MHz into the
script spat out a nice mode line for 1600x1200 at 88 Hz.  Hope it works
for you!)