Ironman70
Level 1 (0 points)

Q: iMac Display Won't Turn on After Sleep (El Capitan) - AppleBacklightDisplay Driver slow error?

I have a late 2015 27" iMac running El Capitan 10.11.3.  Every time I put it to sleep and try waking back up, the display doesn't seem to turn on.  I know the Mac is still running because I can hear the sound volume change when I use the keyboard to change volume.  The only answer is to power down and back on again.

 

Interestingly, I ran pmset -g log under terminal to see if that could provide some info :

 

2016-02-20 10:23:11 +0800 Notification        Display is turned off                                                             

2016-02-20 10:23:11 +0800 Assertions          PID 55(powerd) Summary ExternalMedia "com.apple.powermanagement.externalmediamounted" 00:26:40  id:0x0x80000012c [System: DeclUser kDisp]       

2016-02-20 10:23:11 +0800 Assertions          PID 99(hidd) Summary UserIsActive "com.apple.iohideventsystem.queue.tickle" 00:25:20  id:0x0x9000001d7 [System: DeclUser kDisp]       

2016-02-20 10:23:11 +0800 Assertions          Kernel Idle sleep preventers: -None-       

2016-02-20 10:23:11 +0800 Assertions          PID 55(powerd) Created InternalPreventSleep "com.apple.powermanagement.darkwakelinger" 00:00:00  id:0x0xd00000274 [System: DeclUser SRPrevSleep kCPU kDisp]       

2016-02-20 10:23:17 +0800 Assertions          Kernel Idle sleep preventers: IODisplayWrangler       

Sleep/Wakes since boot at 2016-02-20 09:56:30 +0800    Dark Wake Count in this sleep cycle:0

 

Time stamp                Domain              Message                                                                    Duration  Delay  

==========                ======              =======                                                                    ========  =====  

UUID: EB1B07C9-A29A-40EB-B805-778D08964420

2016-02-20 10:23:17 +0800 Notification        Display is turned on                                                              

2016-02-20 10:23:18 +0800 Kernel Client Acks  Delays to Sleep notifications: [AppleBacklightDisplay driver is slow(msg: SetState to 0)(984 ms)] [AppleHDADriver driver is slow(msg: SetState to 1)(481 ms)]        

2016-02-20 10:23:26 +0800 Assertions          PID 55(powerd) TimedOut InternalPreventSleep "com.apple.powermanagement.darkwakelinger" 00:00:15  id:0x0xd00000274 [System: DeclUser SRPrevSleep kCPU kDisp]       

2016-02-20 10:23:26 +0800                     Summary- [System: DeclUser kDisp] Using AC                                        

Sleep/Wakes since boot at 2016-02-20 09:56:30 +0800    Dark Wake Count in this sleep cycle:0

 

Time stamp                Domain              Message                                                                    Duration  Delay  

==========                ======              =======                                                                    ========  =====  

UUID: (null)

2016-02-20 10:24:04 +0800 Start               powerd process is started                                                         

2016-02-20 10:24:04 +0800                     Summary- [System: No Assertions] Using AC                                         

2016-02-20 10:24:05 +0800 Assertions          Kernel Idle sleep preventers: IODisplayWrangler

 

I put the iMac to sleep at 10:23:11 and the Display turns off.  When I try waking it again 10:23:17, the system thinks the Display turns on - but it doesn't in reality.  Not sure what the potential error messages mean after this, particularly "AppleBacklightDisplay driver is slow".

 

Anyone have any ideas on what's going on here?

iMac with Retina 5K display, OS X El Capitan (10.11.3), null

Posted on Feb 19, 2016 6:40 PM

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Ironman70

Q: iMac Display Won't Turn on After Sleep (El Capitan) - AppleBacklightDisplay Driver slow error?

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  • Helpful answers

  • by joe_7399,

    joe_7399 joe_7399 Feb 21, 2016 6:40 AM in response to Ironman70
    Community Specialists
    Feb 21, 2016 6:40 AM in response to Ironman70

    Greetings Ironman70,

     

    Thanks for using the Apple Support Communities!

     

    I understand that your iMac isn’t waking as you would expect. We know that situations like this can be frustrating, but we’re here to help.

     

    To continue troubleshooting, I suggest working through the steps located in the following article. It sounds like you may have completed some of these already, but the information in the If the previous steps don’t work section will help you further troubleshoot and isolate. 

     

    If your Mac doesn't wake when you expect

    Your Mac might pause a few seconds before it wakes up. If it doesn't seem to wake at all, check for these possibilities:

    • Your screen brightness might be turned down.
    • If you're using an external display, your display might be turned off. 
    • Your Mac might be in safe sleep. To wake from safe sleep, press the power button.
    • Check for a sleep indicator light, if applicable, and make sure that your Mac isn't turned off.

    If the previous steps don't work

    These additional steps may help identify or resolve the issue: 

    • Reset the SMC.
    • Reset NVRAM.
    • Disconnect external devices other than your Apple keyboard, mouse, and display. If that resolves the issue, gradually reconnect your devices, testing each time, until you find the device that is interfering with sleep. Then check the documentation that came with the device, or contact the device manufacturer.
    • Start up in Safe Mode to see if the issue is related to non-Apple startup items, login items, or kernel extensions. 
    • Try to isolate the issue by using another user account. 

    FaceTime is not available in all countries or regions.

     

    If your Mac doesn't sleep or wake when expected - Apple Support

     

    Have a great day!

  • by Ironman70,

    Ironman70 Ironman70 Feb 23, 2016 4:27 AM in response to joe_7399
    Level 1 (0 points)
    Feb 23, 2016 4:27 AM in response to joe_7399

    Yep - tried all of these steps including resetting SMC and NVRAM.  Logging in as a different user account still results in the same problem.  There are no external devices plugged in so really at a loss to know what to do next.

     

    Any other thoughts?

  • by joe_7399,

    joe_7399 joe_7399 Feb 23, 2016 6:02 AM in response to Ironman70
    Community Specialists
    Feb 23, 2016 6:02 AM in response to Ironman70

    Thanks for replying with this information. Because your Mac is still experiencing this issue after the previous troubleshooting, I suggest contacting Apple Support directly. Contacting AppleCare will allow us to dig in to this specific situation further and provide you the best support possible. 

     

    Contact Apple Support - Apple Support

     

    Cheers!

  • by ewf2001,

    ewf2001 ewf2001 Jun 15, 2016 12:49 AM in response to Ironman70
    Level 1 (4 points)
    Jun 15, 2016 12:49 AM in response to Ironman70

    I also had this problem and nothing worked. I just installed MacOS beta1 and i can tell you that finally this annoying problem is gone! My 5K Mac goes to sleep and wakes up normally again.