nMP - How can I get 6 displays to show up in a consistent Order?

Discussion in 'Mac Pro' started by v4film24, Feb 11, 2014.

  1. v4film24 macrumors newbie

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    #1
    Have a nMP 4 core with dual D300s to use for multiple monitor QuickTime playback. No problem to get the displays and set monitor arrangement to playback a movie spanning all the screens - 6 x 1920x1080 - smooth as can be. But each time I reboot the machine the screens are arranged in a different order. Is there a way to always get the same screen arrangement or is the a mini-Display Port/Thunderbolt problem?
     
  2. VirtualRain macrumors 603

    VirtualRain

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    #2
    When I first got my nMP I had a bit of trouble with this with my two displays. However, I think I solved it by putting what I wanted for my primary display on Thunderbolt bus 0 (port 5) and my other display on bus 1 (port 1).

    I may also have done this in two stages... first boot with a single display connected to port 5 and then shutdown and add the 2nd display to port 1 and then restart. From then on, it's always used the same configuration.

    YMMV! :)

    [​IMG]
     
  3. v4film24 thread starter macrumors newbie

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    #3
    Thanks for the advice. Will try this method add one screen at a time to see if I get consistent results using primary display on Port 5. I know I'm pushing the limit with 6 screens at 1920x1080.
     
  4. drunkn macrumors member

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    Aug 12, 2010
    #4
    You think so? It's rated for 6 devices. I would say it's pushing it with 6 30"s (I'm running 3 30"s).
     
  5. macpro2000 macrumors 6502a

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    Apr 20, 2005
    #5
    I'm wanting to run 4 30" ACDs with a nMP...will the D300 be enough or do I need to up to the D500? I will be running all of them at 2560x1600.

    PS: Yes I have all of the Active Dual Link Display adapters
     
  6. simsaladimbamba

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    #6
    The standard or base configuration supports three 4K (though 3840 x 2160 pixel is not 4K, only four times 1080p) displays, which are almost 25 million pixels.
    You have six 1080p displays, which still leaves enough room for more pixels to be pushed. Three "4K" displays equate to 12 1080p displays.
    As mentioned before, six 30" displays with 2560 x 1600 pixel would push it, though mathematically there are still 20 vertical pixels per display left.

    (3840 x 2160) x 3 / number of displays you want /number of pixels you want per display in either horizontal or vertical direction = number of pixels left for either vertical or horizontal direction
     
  7. deconstruct60 macrumors 604

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    Mar 10, 2009
    #7
    "What" is on the screen matter more than the number of those particular screens as to whether need to step up to D500.

    If primarily 2D and static then no. Two monitors each with a complex 3D model then perhaps not.

    Even the D300 can drive 3 4K displays.
     
  8. v4film24 thread starter macrumors newbie

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    #8
    Problem is the order of the screens keep changing with bootup

    Sorry if I misled. No problem pushing the pixels or getting smooth looping QuickTimes with 6 displays. I have them stacked 3 on top & 3 on the bottom. Each time I boot the machine (or restart) the screens are ordered differently. Is there a plist somewhere that holds the screen arrangement? Or do they get dynamically assigned at boot (which seems to occur). Each time I have to go into Displays and change the arrangement which is a pain. I've tried to add them one at a time with reboot after each add as mentioned above. Doesn't seem to solve the problem. Is there software somewhere to fix this? Or is this a minDP/Thunderbolt issue? Thanks for any guidance.
     
  9. deconstruct60 macrumors 604

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    Mar 10, 2009
    #9
    Same problem shows up with a subset or monitors 2, 3, 4, etc.? The another vector is whether they are all native displayPort monitors or dealing with synchronization issues between the active adapters lighting up on boot and the boot process.

    If during boot the mac expects a monitor there and it hasn't shown up yet, perhaps it is moving on.

    The Mac Pro only supports 6 displayPort monitors. It is probably tested with 6 real ones. If trying to approximate that with active adapters intimating being a native DP monitor that is more likely a source of failure.
     
  10. v4film24 thread starter macrumors newbie

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    #10
    Great point deconstruct60 (have always enjoyed your insight). I'm using display port to VGA and DVI and different monitors all of which are on at time of boot. By playing with plugging into different ports on the nMP I've found an arrangement that comes back each time. Each display port seems to sample the monitors in a repeatable order which isn't logical. Thunderbolt Bus 2 seems to go first - Port 4 becomes the boot screen (if there's a monitor there) Port 2 becomes 2nd screen (or boot screen if it's the only one on the bus). Bus 0 goes next and Bus 1 after that. This is repeatable for 1 screen up to six - even plugging the monitors in after booting they will insert themselves into this order. I will keep at it until I know this is not random. But so far it looks like it repeats no mater what.
     
  11. VirtualRain macrumors 603

    VirtualRain

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    #11
    That's consistent with what I reported above about Bus 0 coming before Bus 1, however, I wouldn't have predicted Bus 2 preceding both.
     
  12. deconstruct60, Feb 12, 2014
    Last edited: Feb 12, 2014

    deconstruct60 macrumors 604

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    #12
    In another thread someone posted a block diagram of the Mac Pro. Presuming it is accurate. it may be explanation for the "logic". In that diagram, TB controller for bus 0 is in the "middle". The outputs on the GPU are hooked up from left-to-right. So first TB controller on left gets GPU DP outputs 0 & 1 . The one for TB Bus 0 gets DP port 2 & 3 ( 3 goes through a mux switch so can be diverted to HDMI port if using it). The right TB controller get 4 & 6. If those TB controllers are 2 , 0 , and 1 respectively, then it would make sense.


    Why the TB Bus aren't labeled order. on block diagram.. Phff? ) Looks like the ports on the outside are just labeled top to bottom/left to right like a phone dial pad. The disconnect is having nothing to do with GPU's internal port ordering.

    Should be filed as a bug for Apple. Either a documentation bug (support documents and manuals should highlight the boot order if Mac Pro is sensitive) or fix it so that the display sequence is less sensitive. Apple can decide which category they want to put it in but either way it is a defect.


    I don't think it is TB's fault. If Apple labeled them in the "correct" order they wouldn't be so hard to find.
     
  13. elvisizer, Feb 12, 2014
    Last edited: Feb 12, 2014

    elvisizer macrumors 6502

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    San Jose
    #13
    pretty sure re-ordering the displays is just an OS X quirk. I've seen this same behavior with my 15" retina at work- I have 2 thunderbolt displays connected to it, and the machine is always re-ordering them, changing the wallpapers, etc. Sometimes, the dock will move from one screen to the other while I'm just sitting there working, and I have to reset it using the displays preference pane. I've tried using both TB ports, and daisy-chaining the t-bolt displays, makes no difference. It'll be OK for a few days/week, then decide to flake out again.
     
  14. Cubemmal macrumors 6502a

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    Jun 13, 2013
    #14
    OS X has this problem. I had issues with three monitors and the oMP. I tussled with Apple bug reporter on this one but eventually gave up. Now I've got three monitors on the nMP and it's the same deal, on reboot it reorders the displays. Stupid Apple ...

    I didn't chase it down too much, who cares have better things to do, but found that putting my primary Cinema monitor on TB Bus 2, and the two Thunderbolt monitors on Bus 1 always works. I keep Bus 0 for data only.

    ----------

    Yeah this sounds familiar, I suspect PRAM as the culprit. Maybe if I reset PRAM it would figure itself out properly, but like I say I haven't bothered.
     

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