You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Displayport connected monitor - No signal - after wake from sleep

10.15.7, MacBook Pro 16" 2019, CalDigit TS3 Plus (firmware 44.1).


MBP <--> Power <-> TS3 Plus <-> DisplayPort cable <-> LG Monitor


Frequently, my DisplayPort attached LG 27UK650_600 monitor will not wake from sleep.


The monitor give the following warning: "No Signal. Entering the power saving mode shortly." The monitor attempts to find the signal from the MBP for ~ 27-28 seconds, and then displays the "No Signal. Entering the power saving mode shortly." again.


The displaypolicyd.3:0:0.log is filled with these messages:



If I remove the DP cable from the CalDigit dock and plug it into a thunderbolt port (with a known good DP<-> TB3 adapter), the monitor doesn't display the "No Signal. Entering power saving mode shortly." message at all. It just sits there - black as night.


Interestingly, if I remove power from the MBP, the monitor suddenly wakes up and all is well.


So, two questions:

1) Anyone seeing this issue?

2) Anyone know what those messages in displaypolicyd log indicate?


(Hint: If I shutdown and restart the MBP, everyone's happy...always).

P.S. Fans are spinning like crazy (5200-5600rpm) during this time.


MacBook Pro 16″, macOS 10.15

Posted on Sep 27, 2020 11:49 PM

Reply

Similar questions

4 replies

Oct 4, 2020 2:23 PM in response to o__b

Hi there o__b,


We understand you're experiencing an issue with your MacBook Pro and display not waking from sleep as expected, and we'd like to share a resource that can help.


Check it out here: If your Mac doesn't sleep or wake when expected


Specifically, take a look at the "If your Mac doesn't wake when you expect" and "If the previous steps don't work" sections.


We hope this helps.

Displayport connected monitor - No signal - after wake from sleep

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.