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aurgathor

join:2002-12-01
Lynnwood, WA
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changing VGA resolution on a monitor

Does anyone know how a high resolution monitor limits resolution over VGA, and if there is a reasonably easy way to hack it?

I just got a U3011 (2560x1600 native, but only 2048x1280 over VGA). I do know for the fact that the video card is capable of higher resolution since it works fine with the Matrox TripleHead2Go and 3x19" monitors for a total resolution of 3840x1024. That is 3,932,160 pixels vs 4,096,000 pixels, a mere 4% difference. On the monitor's side, there would be a 36% difference between analog and digital pixel count, but I'm 99% certain that the analog circuitry's bandwidth is higher than what's absolutely needed for 2048x1280.

Can I just send some fake EDID data to the display adapter?

TIA
--
Wacky Races 2012!


shdesigns
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join:2000-12-01
Stone Mountain, GA
On the Nvidia control panel there is Change Resolution -> Customize --> Create Custom Resolution.

I seem to remember something there for ATI also.


tschmidt
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Milford, NH
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reply to aurgathor
As shdesigns See Profile posted need to manually set resolution on the video card. Since there is no EDID entry in the monitor for that resolution it may or may not work but if it doesn't work you can always change resolution it back.

I assume native is HDMI/DVI why not use the digital interface?

/tom

iknow_t

join:2012-05-03
said by tschmidt:

As shdesigns See Profile posted need to manually set resolution on the video card. Since there is no EDID entry in the monitor for that resolution it may or may not work but if it doesn't work you can always change resolution it back.

I assume native is HDMI/DVI why not use the digital interface?

/tom

this may be what he needs to use. it works much better anyway.


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
Reviews:
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reply to aurgathor
I currently have an AMD (6670) card in it, and the AMD SW does not allow me to create a resolution greater than 2048x1280. I will try an Nvidia card to see if that makes any difference.

There are some long stories behind VGA -- for one the monitor will be used by 4 PCs via a KVM, and while I'm planning on getting a new KVM, it will not happen right now. For the record, I'm currently using it via a dual link DVI cable, but that's just a 'test mode' operation.

I already hacked the .inf file but it didn't make any difference, that's why I think that the driver is using the info received via EDID.
--
Wacky Races 2012!


MBBushlen

@shawcable.net
Could be a hardware limitation of the graphics chip. If I recall correctly, the maximum VGA resolution/refresh rate is a function of, among other things the frequency of the RAMDAC in the card.

I had a 24 inch CRT in 1999 which I was able to run at 2560x1600x85hz over VGA, however had to get a card with a fast enough RAMDAC.

With everyone switching away from analog, the newer cards might have very slow RAMDAC's and are now unable to support the higher resolutions over VGA


tschmidt
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reply to aurgathor
said by aurgathor:

I already hacked the .inf file but it didn't make any difference, that's why I think that the driver is using the info received via EDID.

Agree with MBBushlem - Use EDID is unchecked. I think the table is what is in the graphics controller.

/tom

moes
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Cedar City, UT
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reply to aurgathor
I run a custom resolution on my dell IN191ON it's stock resolution is 1366x768.

This is over vga as this display does not have dvi or hdmi connection, but is 16:9 widescreen...