Custom Resolution Utility (CRU)

[CRTFTW]

(02-03-2018 02:00 PM)ToastyX Wrote:  I need to know the exact limits you're hitting to figure out what's going on, and I need the EDID for the Dell as well. Common DisplayPort limits are 300/400 MHz, 360/480 MHz, and 600 MHz.

Ok, I tested some more and found that the issue is that there is some arbitrary pixel clock limit set by the driver, and it is based off the EDID it's reading from displayport in some way.

I tested by moving in 1Hz increments in vertical sync at various resolutions. I found that the Dell P992 is being limited at ~330mHz, the LaCie is being limited to ~530mHz, and the 4k dummy plug, ironically, has the lowest limit at 280mHz.

Notice that in the EDID's, the Dell is labeled as 240mhz max, the LaCie at 420mHz max, and the 4k dummy has no entry. So it's hard to glean any sort of algorithm AMD might be applying here. Those values might have nothing to do with it.

Dell EDID is posted below.