[iyonix-support] MDF for new monitor

I've just acquired and installed a new large flat-screen monitor:  
connected via a KSB switch to both my Iyonix and my Windows PC. The PC 
immediately recognised it and gave me a choice of screen modes up to 
the monitor's native resolution of 1900x1200, which display perfectly 
without any need for adjustment, but I can't get a good display with 
the Iyonix.

For my previous CRT monitor, I started with an existing Monitor 
Definition File for a monitor with similar limits, but the various 
numbers for each mode didn't seem to be very critical. Within 
reasonable limits, I could set any numbers I liked and then adjust the 
monitor manually to make the display fit the screen area. The new one 
tries to adjust itself according to the incoming video stream, which 
complicates trying to work out what it doesn't like.

I've used MakeModes and tried tweaking numbers, both in the MakeModes 
window and by editing the file manually, but the least bad mode I've 
managed to get working so far is 1040x780 (i.e. 4:3 aspect ratio). 
This has the display stretched horizontally to fill the screen, but 
with a few lines invisible above the top of the screen. It's also not 
terribly sharp because of aliasing between the pixels from the 
computer and those on the monitor.

Any mode that I try to create at a higher resolution, even the same 
780 vertically but the correct 1.6 times that horizontally, produces 
one of other of:
large black gaps at both the bottom and the right and the picture 
extending beyond the left-hand edge;
Incoherent display, like an old TV with horizontal hold lost;
"INPUT SIGNAL OUT OF RANGE" message.

I thought of noting the PC's settings and copying them to the Iyonix. 
The PC declares them as follows:

Horizontal:
Front porch: 48
Back porch: 80
Sync width: 32
Scan rate: 74.04 kHz
Active pixels: 1920

Vertical:
Front porch: 3
Back porch: 26
Sync width: 6
Refresh rate: 59.950 Hz
Active pixels: 1200

Pixel clock 154.00 MHz

Significantly, there are no numbers for Left/Top border and 
Right/Bottom border, as called for by MakeModes. However it's not that 
the PC is hiding these numbers: dividing the 154 MHz pixel clock by 
the horizontal total and the vertical total gives the declared 59.95 
Hz frame rate. So it seems that the PC's graphics card doesn't bother 
with the borders that MakeModes wants.

However setting exactly the same values in the MDF causes MakeModes to 
complain in the "Timing diagnostics" area that it needs some minimum 
values and, more importantly, causes the monitor to give the "INPUT 
SIGNAL OUT OF RANGE" message.

Richard
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