Cannot get 75hz on TFT monitor

[Geller Sandor]

On Mon, 31 Oct 2005, Erik Ahlner wrote:

> Anyway, this is not the question whether it's sufficient for me or not, it's 
> a serious BUG imo. The monitor handles 75hz (According to specs, which also 
> has been successfully used in Windows via DVI and in Linux only via VGA), but 
> Xorg refuses to deliver 75hz via DVI!
> With no changes whatsoever to xorg.conf, just switching from DVI output&input 
> to VGA output&input, I get 75Hz.

I have a ViewSonic VP171b-2 with a Radeon 9200, I think you have almost 
the same config.

Add the following line to the Device section:

     Option "IgnoreEDID" "true"

And these lines to the Monitor section:

     HorizSync   30 - 82.0
     VertRefresh 50-85

     # 133 MHz, 80.8 kHz, 75.0 Hz
     Modeline "1280x1024" 132.59 1280 1320 1384 1640 1024 1026 1030 1078

     # 80 MHz, 60.6 kHz, 75.0 Hz
     Modeline "1024x768" 79.51 1024 1056 1120 1312 768 770 773 808

     # 49 MHz, 47.4 kHz, 75.0 Hz
     Modeline "800x600" 48.54 800 824 888 1024 600 602 604 632

Of course you can generate your own modelines, I generated these with 
videogen -m=1280x1024 -mdc=140 -mhf=82 -mvf=85 -dvf=75

Regards,

   Geller Sandor <wildy at petra.hos.u-szeged.hu>