Unable to logon with DisplayPort connected

Discussion in 'Mac Pro' started by Spacedust, Apr 1, 2017.

  1. Spacedust macrumors 6502a

    Joined:
    May 24, 2009
    Location:
    Poland
    #1
    When I connect my 4K Philips display on boot to flashed HD7950 card it simply refuses to boot.

    If I disconnect the 4K display and connect it right after booting then everything works fine. What's the reason for this? All works fine on HDMI and DVI.
     
  2. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #2
    Flashed 7950 can't boot with a 4K 60Hz screen connected. That's a known issue for long time.
     
  3. Spacedust thread starter macrumors 6502a

    Joined:
    May 24, 2009
    Location:
    Poland
    #3
    Why flashed HD7870 boots fine?
     
  4. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #4
    Because Pitcairn is not Tahiti.
     
  5. Gazember, May 1, 2017
    Last edited: May 1, 2017

    Gazember macrumors member

    Joined:
    Apr 5, 2017
    #5
    I have the same issue. It has to do with port mapping and the type of kludge work that flashing a card actually is. Card designs are slightly different and usually there is a single GPU ROM that people keep using for all 7950 cards.

    Display Ports never work for me regardless of boot/plug sequence. However, the HDMI port works flawlessly up to 4K, but only at 30Hz refresh rate.
     
  6. Fl0r!an macrumors 6502a

    Joined:
    Aug 14, 2007
    #6
    Does ist show a bootscreen on a DP1.2 display?
     

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