Multiple Displays not recognized at startup

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Multiple Displays not recognized at startup

MacPro Late 2013

Yosemite 10.10.3

AMD FirePro D500 3072 MB

I have three monitors connected with active displayport->DVI adapters. I turn on the computer, it boots up (I know only 1 will work during boot) and when it reaches the OS, usually only 2 monitors are on and working. The third, which is sometimes the same one that WAS on during boot, is now black. I have to reseat the cable to get the video card to recognize the third monitor. After that everything is ok until I reboot and then about 19 out of 20 times this behavior repeats itself. There is that 1 in 20 chance that it works fine after a reboot or shutdown. I feel like this is probably a firmware issue with the video cards but I am not sure.

I have the monitors plugged in ports 1, 2, and 5, according to this article. Any help or insight you can provide would be greatly appreciated. I love this computer and this issue is a relatively minor annoyance, but I would love to fix it if possible!

Mac Pro (Late 2013), OS X Yosemite (10.10.3)

Posted on Jun 28, 2015 7:39 AM

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Answer 1

lllaass

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Jun 28, 2015 8:13 AM in response to cdb4113

What is the resolution of the three monitors?

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Answer 2

cdb4113 Author

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Jun 28, 2015 9:03 AM in response to lllaass

All three are the same model 24" ASUS LCD at 1920x1080 and all three active displayport adapters are the same make/model.

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Answer 3

lllaass

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Jun 28, 2015 9:10 AM in response to cdb4113

What specific brand ACTIVE mini displayport>DVI adopter? Some work better than others

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Answer 4

cdb4113 Author

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Jun 28, 2015 9:11 AM in response to lllaass

I am using the apple adapters

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Answer 5

lllaass

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Jun 28, 2015 9:14 AM in response to cdb4113

Do you mean the $99 dual-link adopters and require power from a USB port?

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Answer 6

cdb4113 Author

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Jun 28, 2015 9:23 AM in response to lllaass

yes, and i have them plugged in to a usb hub with constant power.

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Answer 7

Jun 30, 2015 2:54 PM in response to cdb4113

10.10.4 available today, 30 June 2015, supposedly with fixes for some display problems.

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Answer 8

cdb4113 Author

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Jun 30, 2015 5:23 PM in response to Grant Bennet-Alder

I was excited when I read this but the issue is still there after applying the update and rebooting a couple times. I have also confirmed that whatever monitor I have connected to Thunderbolt Bus 2 (according to this article) is recognized when I see the apple logo, but then is not recognized when I reach the login screen until I reseat the cable. Also, (and this is strange) it does not matter if I reseat the usb or the mini displayport, either will make the computer recognize the adapter. This discovery led me to remove the usb hub and plug the adapters into the tower directly through usb AND mini displayport but the behavior was still present.

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Answer 9

cdb4113 Author

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Jun 30, 2015 5:33 PM in response to cdb4113

Not sure if this matters or not but I just found this articleand it looks like my firmware might not be the same. The article says I should have :

"Boot ROM Version" is "MP61.0116.B04", and the "SMC Version" contains "2.20f18"

But my system says I have:

"Boot ROM Version" is "MP61.0116.B15", and the "SMC Version" contains "2.20f18"

Could this have something to do with it?

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Answer 10

cdb4113 Author

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Jul 3, 2015 2:13 PM in response to cdb4113

I just got back from the Apple Store, we tested three monitors with my tower...All three worked properly when using the $999 27" Apple thunderbolt displays, so it looks like it is an issue with the displayport to dvi adapters or my monitors themselves might not be compatible. I did notice the adapters are dual link dvi-d and my cables are single link dvi-d, so my next troubleshooting step will be to get some dual link dvi-d cables and see what happens. I am starting to think there is a handshake on the dual link that I am missing because of my cables. Fingers crossed!

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