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george-brooks

macrumors 6502a
Original poster
Oct 31, 2011
732
16
Brooklyn, NY
Hi everyone,
I have two displays hooked up to my new mac pro, which I've had for about 2 months now. One is an NEC PA271W which is connected with an apple Dual Link DVI adapter, and the other is a PA241W, connected with the standard DVI-MDP adapter. Both are connected to separate thunderbolt busses, as suggested by apple.

Here's the issue:
9 times out of 10, when waking from sleep, only the PA241 wakes along with the computer. The computer recognizes that the other display is attached, but it won't wake with the computer (I know its recognizing it because the login window does not show on the one that is working, only the background image, as it is set to be the secondary display). About half the time, if I cycle the power on the 271, it starts working no problem. But the other half, I have to unplug the dual link adapter and plug it back in. Usually this only works if I hook it back up to a different thunderbolt port. Sometimes I have to try multiple times.

Does anyone have any idea what might be going on here? Do I have a bad dual link adapter? Any help would be much appreciated. It's not a huge deal, but it is quite annoying that my new $6,000 computer doesn't "just work."

Thanks in advance!
 

vett93

macrumors 6502
Jul 27, 2014
279
39
California
My almost 3-month old Mac Pro has the same problem. I have been working with AppleCare for the last 2 months. I have worked with 2 senior advisors from Apple and they collected traces from my computer twice for Apple's engineers to debug. Yesterday, they asked me to try my Mac Pro with one monitor and see if I have the same problem.

According to this senior advisor, there are a few of us who still have this problem. I recommend that you contact AppleCare as well.
 

cebseb

macrumors regular
Feb 21, 2011
247
1
Still haven't been able to figure this one out. Any ideas?

I had a similar issue with my mac pro. I'm using dual LG 34um95s and whenever my monitors go to sleep, only one will wake-up while the other detects no signal and goes into "power save" mode.

After weeks of failed attempts at settings and cable brands, I fixed it by going into my monitor's own hardware settings and enabling displayport 1.2.

If your monitor has that option, I suggest you try it.

Cheers.
 

george-brooks

macrumors 6502a
Original poster
Oct 31, 2011
732
16
Brooklyn, NY
I had a similar issue with my mac pro. I'm using dual LG 34um95s and whenever my monitors go to sleep, only one will wake-up while the other detects no signal and goes into "power save" mode.

After weeks of failed attempts at settings and cable brands, I fixed it by going into my monitor's own hardware settings and enabling displayport 1.2.

If your monitor has that option, I suggest you try it.

Cheers.

Thanks for the info, I'll check that out. Do your monitors have Displayport connections? I believe mine only have DVI.

Also, I spoke to Apple and they suggested resetting the SMC and NVRAM. Haven't been able to do a whole lot of testing yet but so far that seems to have worked.
 

cebseb

macrumors regular
Feb 21, 2011
247
1
Thanks for the info, I'll check that out. Do your monitors have Displayport connections? I believe mine only have DVI.

Also, I spoke to Apple and they suggested resetting the SMC and NVRAM. Haven't been able to do a whole lot of testing yet but so far that seems to have worked.

Yes, mine do have displayport. I guess my suggestion is moot for you. Sorry!
 

HenryAZ

macrumors 6502a
Jan 9, 2010
690
143
South Congress AZ
Thanks for the info, I'll check that out. Do your monitors have Displayport connections? I believe mine only have DVI.

My PA271W (since sold) had Displayport. My PA301W has it. I thought all of the PA series did. Maybe there was an earlier version that did not ??

A Mini Displayport -> Displayport cable is the way to go if you can. The newest PA series monitors are even coming with the cable provided.
 

JmanInSF

macrumors member
May 11, 2010
34
0
I have, presumably, the same problem. Sadly, my solution to this is to never let my screens go to sleep. I know some folks will warn against various forms of 'decay' to my monitor(s) if they're on all the time, but my screen saver is set to be nearly all black. I'm hoping this lessens the wear on the screen.

It's a huge pain when it does happen... Typically after a restart. Power off/on, replug, swap ports... Lordy.
 

megalaser

macrumors 6502
Nov 17, 2009
345
66
Same problem - big annoyance . . . mine is actually with two 27 inch iMac's in target display mode, I have an older 2009 iMac connected as mini display port as the main monitor and this wakes every time, the other iMac is a 2011 model connected via Thunderbolt and it never wakes up with the Mac Pro, I have to screw around manually waking it each time. if anyone finds a solution to this or can tell me how to change any settings on the 2011 iMac so that it wakes up I would appreciate it.
 

chfilm

macrumors 68040
Nov 15, 2012
3,298
1,984
Berlin
Same issue with 2 Thunderbolt Displays.

Sometimes another annoying issue occurs, since I also have a BenQ projector attached as a third display.

The projector is always recognized even when in standby. But when I turn it on, it will sometimes, only sometimes lower the screen resolution of both Tb displays to 1080p and I have to reset it manually. Very annoying.

Phone Support couldn't help me.
 

george-brooks

macrumors 6502a
Original poster
Oct 31, 2011
732
16
Brooklyn, NY
My PA271W (since sold) had Displayport. My PA301W has it. I thought all of the PA series did. Maybe there was an earlier version that did not ??

A Mini Displayport -> Displayport cable is the way to go if you can. The newest PA series monitors are even coming with the cable provided.

You're right, it does, my mistake. It doesn't have HDMI, that was going to be my first solution. I will definitely get that cable, I'd love to not have the giant dual link adapter hanging off my desk.

A note to everyone, resetting NVRAM and SMC seems to have more or less done the trick, I've only had the issue once since doing so.
 

snouter

macrumors 6502a
May 26, 2009
767
0
Same.

Apple 27" Cinema filres up as the main monitor. HP ZR2740w needs me to reboot or plug and unplug the cable at the nMP.
 

Cubemmal

macrumors 6502a
Jun 13, 2013
824
1
I've got two TB displays and a 27" Cinema display and haven't seen this at all.

Maybe try different port configurations. I have the two TB's on bus 2 (top left) on the two different ports and the Cinema on bus three (top right).
 

Cubemmal

macrumors 6502a
Jun 13, 2013
824
1
What other devices are connected to your Mac Pro? I am suspecting if my problem is caused by devices connected to the USB ports. They may have drawn more power than Mac Pro can handle. The devices on the I/O board share one power supply. See the following diagram:

http://i.imgur.com/ItIqxDY.png

Two Promise Pegasus2 (4/empty populated with a SSD HD arrays) on the third TB bus (0), a bunch of USB, a firewire device. USB direct from the MP is just a USB 3 card reader and the USB connection to the Cinema, all the rest of the USB comes off the TB displays.
 
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