Displayport and Ultrawide leaves black screen/no signal

Discussion in 'Mac Pro' started by echelon4, May 11, 2018.

  1. echelon4 macrumors newbie

    Joined:
    May 3, 2014
    #1
    I picked up a Mac Pro 2012 with a fresh High Sierra install. It has a flashed Radeon R9 280X 3gb (2x Mini DP, HDMI, DVI) video card installed.

    I'm hoping to have 2 displays attached (neither scaled or using adaptors). First is a Dell 1920x1080 (rotated 270 degrees) and it works fine with a Mini DP/DP cable, though the screen does not rotate until after log-in and I can live with that. The other display is a LG 2560x1080 ultrawide display and only produces a black screen with a Mini DP/DP cable. It seems to be recognized but nothing is displayed. I get some scaled resolutions through DVI, but not the native 2560x1080. I do get 2560x1080 with a HDMI cable but I'm hoping to use displayport.

    Any ideas? I've read issues with Sierra/High Sierra and scaled resolutions, but I'm avoiding them. Thanks!
     
  2. h9826790 macrumors G4

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #2
    If the display support above DP 1.2, try set it to DP 1.2 or 1.1.
     
  3. orph macrumors 68000

    orph

    Joined:
    Dec 12, 2005
    Location:
    UK
    #3
    i think it will work over DVI as long as it's a "dual link DVI cable" and "dual link DVI port" at 2560x1080.
    https://en.wikipedia.org/wiki/Digital_Visual_Interface
    dual link DVI max rez 2560 × 1600 @60hz (single link is only 1920x1200)

    so if you have a pile of DVI cables worth a look to see if you have a dual link one

    DP is a better tho if you can make it work (is it higher bit depth and refresh rate ?)
     
  4. echelon4 thread starter macrumors newbie

    Joined:
    May 3, 2014
    #4
    @h9826790 - I'm not sure how to change display support, I don't see it any setting (LG 29UB55-B).

    @orph - The cable I tried is DVI-I Single Link. I currently use it on my 2008 Mac Pro @ 2560x1080.
     
  5. orph macrumors 68000

    orph

    Joined:
    Dec 12, 2005
    Location:
    UK

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