Dell P2715Q to MBP 15" - Thunderbolt cable to MiniDP input doesn't work?

Discussion in 'MacBook Pro' started by victorhooi, Oct 22, 2016.

  1. victorhooi macrumors member

    Mar 29, 2011
    I have a Dell P2715Q that I'm trying to connect it to a Macbook Pro 15" Retina.

    The Dell has a MiniDP input - I'm using a Apple Thunderbolt cable to connect this to the Thunderbolt port on my Macbook. I assumed it would be just plug-and-play - however, the Dell complains that there is no signal coming on MiniDP.

    If I use a MiniDP-to-DisplayPort cable to connect the MBP to the monitor, it does work.

    Is the Thunderbolt cable the right thing to use here? Or is there something I've missed? (I had previously thought a Thunderbolt cable could do everything a MiniDP to MiniDP cable could do, plus data transfer).
  2. JTToft macrumors 68040

    Apr 27, 2010
    Aarhus, Denmark
    I do believe it should work. But why are you not just using the mDP-DP since it apparently doesn't?
  3. Floris macrumors 68020


    Sep 7, 2007
  4. Freyqq macrumors 601

    Dec 13, 2004
    You need a mini-dp to mini-dp or dp to mini-dp cable. Thunderbolt is a completely different protocol.
  5. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    See Page 12 of the Product Manual, Electrical Specifications, Video input signals - "DP 1.2/HDMI 1.4/MHL 2.0 signal input support"

    TB 1/2 carries DP 1.1a, which is not compliant with Dell's specs for this display. I own about 2 dozen of P2715 displays, in my small biz and home office, FWIW...

    For some reason, Apple's computers seem to have allowed TB cables to work with some displays under 10.11 and earlier OS versions but not in Sierra, which has Metal and other OS-specific support features - leading me to believe that Apple has cracked down a bit. I'm not interested in a debate here - TB cables worked with my P2715Q displays under 10.11 but not 10.12; regardless, I use only Accell DP 1.2-compatible cables now for our BenQ/Eizo/Dell displays anyway, and get nothing but black screens with our TB cables (all Apple cables). I do recall Apple's enabling of features with 10.9.3 and 10.10.3 - specifically those two OS updates - that enhanced my experience with my P2715Q displays, so I'm not too surprised that Apple changed things up again with Sierra.
  6. jerryk macrumors 601

    Nov 3, 2011
    SF Bay Area
    I wonder if Apple is preping some new 4/5K monitors and does not want the competition.
  7. killawat macrumors 65816

    Sep 11, 2014
    I think it was you who recommended those cables in a different post, thanks for that. Their's are the only one that keep the connection alive to my dell display, all the others disconnect when I put the machine to sleep.
  8. campyguy macrumors 68040

    Mar 21, 2014
    Portland / Seattle
    I do believe that's an option, even if Dell is one of the Platinum sponsors of the upcoming FCPX expo set for the same day as Apple's reveal. My more-likely scenario is that - and this is a bit of IMHO - several graphics apps I use in my shops include Solidworks, AutoCAD, and VectorWorks, which have certified configurations (including graphics cards); only the stock Eizo displays we have have compliant cabling shipped with the displays, and my hardware reps only roll their eyes at the Dell-supplied COXOC-manufactured cables - using a four-letter-word that isn't "junk" when describing anything with the COXOC brand on it...

    I *am* looking forward to new toys, er..., hardware being announced next week. A couple of updated Apple displays using the new port configuration will be welcomed by me - one cable replacing the spaghetti options we now have, a big step forward IMHO...
    --- Post Merged, Oct 22, 2016 ---
    Guilty, and a pleasure at that... :D

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