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What is the minimum porch, sync, blanking, etc...?

Posted: 27 Jul 2020, 01:07
by ELK
I'm trying to get the most out of my dummy plug. Custom resolutions in nvidia are not showing up and the displayID method is not working. Wild guess is that it's seen as a dvi. I think dual link, maybe single. Reguardless DisplayID resolutions are not showing up so I must use regular restrictions (i think it's 600 something pixel clock)

I would like 3840x2160@90hz, but I cannot achieve 90hz. I would instead like the highest refresh rate possible. To achieve this I need the slowest scan out possible lol.

What is the minimum:
Horizontal front porch
Vertical front porch
Horizontal sync width
Vertical sync width
horizontal back porch/blanking/total
vertical back porch/blanking/total

Re: What is the minimum porch, sync, blanking, etc...?

Posted: 27 Jul 2020, 07:36
by Chief Blur Buster
ELK wrote:
27 Jul 2020, 01:07
I'm trying to get the most out of my dummy plug. Custom resolutions in nvidia are not showing up and the displayID method is not working. Wild guess is that it's seen as a dvi. I think dual link, maybe single. Reguardless DisplayID resolutions are not showing up so I must use regular restrictions (i think it's 600 something pixel clock)

I would like 3840x2160@90hz, but I cannot achieve 90hz. I would instead like the highest refresh rate possible. To achieve this I need the slowest scan out possible lol.

What is the minimum:
Horizontal front porch
Vertical front porch
Horizontal sync width
Vertical sync width
horizontal back porch/blanking/total
vertical back porch/blanking/total
Minimums are display dependant, the firmware/scaler can have problems with too small numbers.

If the display firmware is not the limiting factor, then usually 8,8,8 for horizontals (24 pixel horizontal blanking) and 1,1,1 for verticals (3 pixel vertical blanking)

This would result in:
Horizontal Total = Horizontal Resolution + 24
Verticcal Total = Vertical Resolution + 3

The signal structure looks like this, taken from Custom Resolution Utility Glossary 101.

Image