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Mid 2012 MP and LG-34um95 wake from sleep problem

kepgnar

kepgnar

macrumors newbie
Original poster
Dec 30, 2015
12
2
You guys seem like experts, I can not figure out this problem for the life of me...

I have a Mid 2012 Mac Pro with the ATI Radeon HD 5770 1024MB

I recently purchased the LG 34UM95-P and have it connected via a Mini-DisplayPort to DisplayPort cable that is DP 1.2 compatible.

Monitor works great, resolution is wonderful, however once the Mac goes to sleep, the monitor enters it's own standby mode, and then will not receive a signal from the Mac on wake. It will say "no signal detected" and go back into energy saving mode.

For the first few weeks I had it, it would do the same initially, but after going back into energy saving mode, if I pressed the monitor power button, it would then receive the video signal and work normally. But now it will never get the signal.

I have also tried going DVI-to-DisplayPort, same issue. This is not an issue when going from Mini DP to HDMI, however I only get 30Hz and this is unacceptable.

It is impossible to find any examples online of someone with this same configuration and problem. I am fairly certain it has to with the Mac/video card, because my MBA and rMBP do not cause the same issue when using the same MiniDP to DP cable.

Does anyone have any thoughts or advice on this? I've even begun looking at replacing the video card due to how annoying and nearly unusable this is. The monitor is about 6 weeks old at this point so I cannot return it.

Anyway, any thoughts or advice that might get this working again is insanely appreciated. Thanks!
 
Many people have this problem. Did you try the usual fix of disabling Display Port 1.2 in the monitor's settings? If not, I'd try that first.
 
i thought i had tried it both ways. but i just disabled it again, and will monitor for a bit (pun intended.)
 
update: I have tried this with DisplayPort 1.2 both disabled AND enabled, the issue persists. Furthermore, I have the monitor's auto-standby option turned off.

As it stands, the monitor only "works" (displays video from the Mac Pro) when first powering on the Mac Pro. If the machine goes to sleep at any time, I am unable to get the monitor to display video again, until powering off the Mac and powering it on again.

What is the difference between waking from sleep and a fresh boot? Surely there's some way to get to the bottom of this.
 
The other problem I've seen is that certain Startech DP cables have the power wire incorrect, according to reviews on Amazon. But if you've used the cable on other computers and it wakes fine for those, the cable is probably fine.

I see in the other thread someone narrowed it down to El Capitan, but I am doubtful of that because this LG has been spotty for waking from sleep on Macs before El Capitan was released.

It's disappointing really because LG specifically advertised this monitor as a Mac compatible monitor, and clearly designed it for Apple users by including a Thunderbolt hub at a time when almost all computers with Thunderbolt were Macs, and by including OS X software.
 
I was encountering the same issue with my Mac Pro (with GTX 680) and 34UM95-P. Unplugging the DP cable and plugging it back in again would get the display to reconnect, but obviously that's not a satisfactory long-term solution. Installing the newest Nvidia drivers fixed the problem for me. Have you tried updating the ATI drivers?
 
I have the same issue.

2010 mac pro with AMD R9 380 (
) This is a PC bare card, HDMI does not work on it, so at least i know those with the stock ati 5770 have the same problem.

Often the monitors screen will be black, when i press a key, i get the 'no input signal' i then have to wait for the monitors standby light to flash, then when i press the button, it comes on - about 15-20 seconds)

for me its a bit annoying, can live with it but would be good to get a fix.

Im going to uninstall the included software (LG Screen Split), maybe that had a thing to do with it.
 
I have not discovered any fixes to this, but here is my current workflow:

Real issue seems only to be actual waking from sleep. So...
I have computer set to never sleep, and screen saver to start after a few minutes. I do have the machine scheduled to power off daily at 11pm.

If I'm powering the machine on for the first time on a specific day, I press the power button on the Mac Pro, wait 5 seconds, then press the power button on the monitor. This works 98% of the time.

To me this is a terrible workaround, but it does indeed work. I don't know if that helps anyone, but that's my current state with this monitor.
[doublepost=1458596930][/doublepost]
savoirfaire said:
I was encountering the same issue with my Mac Pro (with GTX 680) and 34UM95-P. Unplugging the DP cable and plugging it back in again would get the display to reconnect, but obviously that's not a satisfactory long-term solution. Installing the newest Nvidia drivers fixed the problem for me. Have you tried updating the ATI drivers?
Click to expand...


I will look when I get home and see if there is a driver update for my card. I REALLY hope there is, and that it fixes the issue for good. I feel bad when my wife says "why doesn't it just work like the other computer (2011 iMac)?"
 
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I deal with this problem a fair amount with my 2013 nmp and this monitor. Sometimes it won't wake up from sleep unless I do a hard restart, which, with four RAIDS running, is hardly ideal. The other issue I have is that, occasionally, my monitor won't come on even with a hard cpu restart. It stays in energy saving mode. I have found that hitting keys on the keyboard while also moving the mouse can wake the monitor, but this isn't a consistent solution. I too love the monitor but I won't buy another LG unless they fix this. I know it's possible that apple is responsible, but I have owned this monitor for nearly two years, through many OS X iterations, and it has never worked correctly. How LG could have ever shipped this monitor, advertised as being ideal for the mac pro, without discovering this obvious bug is utterly beyond me.
 
At least i know it's happening with thunderbolt as well as Displayport (New and Cheesegrater MacPros)

I find myself turning the monitor off at the back (when not using it for a long period, ie at night) - there's a big switch which is far better than the dainty little joystick on the front of the monitor - one physical button does everything - ooooo edgy design concept. NO how about a physical, reliable simple on / off switch you muppets!

Today i woke my mac, THEN turned the physical on / off switch at the back and it came straight on - could be a solution or luck of the draw. The big switch at the back has a dimple on it - when this is pressed in, the monitor is on, so easy to feel if its in the on or off position. I've also found it fairly easy to find when sat down and sticking your arm around - sort of get used to the location.

Just wish they'd put this on the front. The joystick is sometimes unreliable and slow and feels like it's lifespan could be in jeopardy if pressed all the time. I also find I leave the brightness as is vs changing it via the cumbersome joystick if i want to make it brighter etc...

EDIT

Turn monitor off on back
when you come back, press a key on keyboard (i press command and tab a few times)
THEN Turn monitor on

Does seem it needs more time than normal to get a signal

Slightly more tedious but overall quicker than waiting for the 'no signal screen'

Just done this, could be a fluke but seems logical.
 
Last edited:
For what it's worth, I have the Dell UltraSharp U3415W which uses the same 21:9 IPS LCD panel as the LG 34UC97. But it does have different electronics and it works fine.

I was looking into the LG, but all the complaints in the Massdrop forums scared me away.
 
eskmo3 said:
Posting up to let you guys know its more then just a monitor sleeping issue.

I too have this issue since i bought the monitor in 2015. (2013 nMP + thunderbolt out to display port in)

Often times it was tough to get the monitor to wake up but even more so while working, almost everyday it would just go black. I would wait for a minute, move my mouse and it would come back. This did;t really bother me until last week.

I started working with my computer over a network. I realized its actually the mac that is going into sleep mode via the monitor. I was in the control room where my mac is and noticed for the first time (after repeatedly being disconnected from a network while doing file transfers) that the power button was pulsing its slow sleep mode.

All my settings tell my mac not to fall asleep.

I just got back from picking up the nMP from the genius bar, after two days of testing they said they can't find any hardware issues and suggested it might be a software thing. Solution in their eyes is to completely wipe and reinstall / drag files back over, NOT Time Machine. As a solution thats totally undoable as I'm in the middle of a number of projects.

I'll keep posting as i learn more.
Click to expand...


It definitely is an issue with OS X sleeping, and upon waking the machine, the signal is either not being sent by the Mac, or not being received by the monitor. (as a side note, none of these issues occur when booting to my Bootcamped Windows drive installed in the same machine.)

My Mac however does not go to sleep unexpectedly, it sounds like you're saying yours does. My best workflow involves 2 things:

1. when powering on the Mac:
  • I press the power button
  • wait 5 seconds
  • press the power button on the bottom of the monitor
  • Mac will POST a few seconds after that (2012 Mac Pro, takes about 10 seconds total to POST after pressing power button)
  • Press a key on keyboard repeatedly (keyboard runs directly to Mac, so really has no effect on the scenario, but makes me feel better)
  • 99% of the time, the monitor will get the signal and start displaying video about halfway through the boot up progress bar.
2. when using the Mac:
  • I have the machine set to never sleep, and scheduled to power off every day at 11pm.
  • I also have screen saver set to automatically start after a few minutes, or with a hot corner activation.
  • 99% of the time the signal stays intact and there are no issues.

I hope that helps somebody else. I really should just say **** it and get a different monitor, as it's truly an unnecessary pain in the ass.
 
I will say that using the web drivers helped, but I am having these brief episodes where the screen will go black for about a second or two then come back again. Happens maybe 2 or 3 times a night. Annoying. It's really too bad because the picture with this monitor is otherwise gorgeous. Haven't gotten to the point where I've said screw it and gotten a new monitor... yet.
 
savoirfaire said:
I will say that using the web drivers helped, but I am having these brief episodes where the screen will go black for about a second or two then come back again. Happens maybe 2 or 3 times a night. Annoying. It's really too bad because the picture with this monitor is otherwise gorgeous. Haven't gotten to the point where I've said screw it and gotten a new monitor... yet.
Click to expand...

what web drivers are you speaking of specifically? can you link to them?
 
kepgnar said:
I have not discovered any fixes to this, but here is my current workflow:

Real issue seems only to be actual waking from sleep. So...
I have computer set to never sleep, and screen saver to start after a few minutes. I do have the machine scheduled to power off daily at 11pm.

If I'm powering the machine on for the first time on a specific day, I press the power button on the Mac Pro, wait 5 seconds, then press the power button on the monitor. This works 98% of the time.

To me this is a terrible workaround, but it does indeed work. I don't know if that helps anyone, but that's my current state with this monitor.
[doublepost=1458596930][/doublepost]


I will look when I get home and see if there is a driver update for my card. I REALLY hope there is, and that it fixes the issue for good. I feel bad when my wife says "why doesn't it just work like the other computer (2011 iMac)?"
Click to expand...

Ha! so funny

When I had a R9 280X flashed I was having the same problem and doing the exact same workaround of turning the screen on afterwards

With RX 580 and now VEGA, no problem at all
 
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