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I have a MacBook Pro M1 connected to an Acer EB321HQU external display through a J5Create USB hub. I have the MacBook set to put the display to sleep when idle, rather than using the screensaver. I normally use it in clamshell mode, although the problem I'm having happens with the lid open, too. The external display is set to mirror the internal.

When the computer's display sleeps, either because of the idle timer or manually with Ctrl+Shift+Power, the external display initially goes completely black after displaying a No signal message. And until recently, it stayed like this until I touched the keyboard to wake it up.

But lately something has changed. After a few minutes (once it was less than 5 minutes, another was more than 10) the external display backlight comes back on and stays on. The display is black, but there's a glow of the backlight, and it's annoying when the lights are out. It happens by itself, I think every time the display sleeps. I haven't touched the computer when it happens, and there are no notifications popping up (normally when a notification occurs during display sleep it wakes the display to show it for a few seconds, then puts the display back to sleep).

The display is still in standby mode when this happens -- the power light is amber, not blue.

When I tried this with the MacBook lid open, I couldn't see any change on the internal display, it was still completely black.

This started this week when I came back from a trip where I took the computer with me. I had installed the July 12 MacOS update while I was away, but the description of that minor update doesn't seem related to displays. I may have tweaked a few system settings while I was away -- when I'm away from home I turn on the option to require a password to return from screensaver or lock screen.

Here's the output of pmset -g log from one of the recent occurrences. Any idea what's triggering it and how I can get things back to the way they were before I went away?

2023-07-26 21:51:36 -0400 Sleep                 Entering DarkWake state due to 'Software Sleep pid=96242':TCPKeepAlive=active Using AC (Charge:100%)           
2023-07-26 21:51:36 -0400 Assertions            PID 357(powerd) Created InternalPreventSleep "com.apple.powermanagement.darkwakelinger" 00:00:00  id:0x0xd000088a1 [System: PrevIdle DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 21:51:36 -0400 Notification          Display is turned off                                                                 
2023-07-26 21:51:36 -0400 Assertions            PID 357(powerd) Released PreventUserIdleSystemSleep "Powerd - Prevent sleep while display is on" 00:00:11  id:0x0x100008810 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 385(timed) Summary NoIdleSleepAssertion "com.apple.timed.ntp" 00:00:00  id:0x0x1000088a2 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 405(bluetoothd) Summary PreventUserIdleSystemSleep "com.apple.BTStack" 00:03:53  id:0x0x10000880c [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 357(powerd) Summary ExternalMedia "com.apple.powermanagement.externalmediamounted" 56:01:46  id:0x0x800008000 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 357(powerd) Summary UserIsActive "com.apple.powermanagement.lidopen" 00:14:29  id:0x0x9000086c4 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 405(bluetoothd) Summary UserIsActive "Bluetooth LE HID Activity" 00:00:11  id:0x0x900008720 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 413(WindowServer) Summary UserIsActive "com.apple.iohideventsystem.queue.tickle serviceID:100020d1c service:AppleUserHIDEventService product:MX Keys eventType:3" 00:00:00  id:0x0x9000086c5 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 357(powerd) Summary InternalPreventSleep "com.apple.powermanagement.darkwakelinger" 00:00:00  id:0x0xd000088a1 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 357(powerd) Summary InternalPreventSleep "com.apple.powermanagement.acwakelinger" 00:00:10  id:0x0xd0000885d [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:36 -0400 Assertions            PID 383(apsd) Summary InteractivePushServiceTask "com.apple.apsd-login" 00:00:00  id:0x0x12000088a3 [System: PrevIdle DeclUser SRPrevSleep IPushSrvc kCPU kDisp]          
2023-07-26 21:51:41 -0400 Assertions            PID 405(bluetoothd) Released PreventUserIdleSystemSleep "com.apple.BTStack" 00:03:57  id:0x0x10000880c [System: PrevIdle DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 21:51:41 -0400 Assertions            PID 357(powerd) TimedOut InternalPreventSleep "com.apple.powermanagement.darkwakelinger" 00:00:05  id:0x0xd000088a1 [System: PrevIdle DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 21:51:41 -0400 Assertions            Summary- [System: PrevIdle DeclUser SRPrevSleep kCPU kDisp] Using AC(Charge: 100)          
2023-07-26 21:52:07 -0400 Assertions            PID 96245(AddressBookSourceSync) Released PreventUserIdleSystemSleep "Address Book Source Sync" 00:00:30  id:0x0x1000088c7 [System: DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 21:52:10 -0400 Assertions            PID 357(powerd) TimedOut InternalPreventSleep "com.apple.powermanagement.acwakelinger" 00:00:44  id:0x0xd0000885d [System: DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 21:52:10 -0400 Assertions            Summary- [System: DeclUser kDisp] Using AC(Charge: 100)          
2023-07-26 21:52:10 -0400 Sleep                 Entering Sleep state due to 'Software Sleep pid=96242':TCPKeepAlive=active Using AC (Charge:100%) 757 secs  
2023-07-26 21:52:12 -0400 Wake Requests         [process=mDNSResponder request=Maintenance deltaSecs=7198 wakeAt=2023-07-26 23:52:10 info="upkeep wake"] [*process=dasd request=SleepService deltaSecs=903 wakeAt=2023-07-26 22:07:15 info="com.apple.dasd:0:com.apple.CoreAnalytics.2Hours"] [process=dasd request=TimerPlugin deltaSecs=919 wakeAt=2023-07-26 22:07:31 info="com.apple.dasd:505:com.apple.Safari.SafeBrowsing.BrowsingDatabases.Update"] [process=powerd request=UserWake deltaSecs=5332 wakeAt=2023-07-26 23:21:05 info="com.apple.alarm.user-visible-com.apple.CalendarNotification.EKTravelEngine.periodicRefreshTimer,644"]           
2023-07-26 21:52:12 -0400 PM Client Acks        Delays to Sleep notifications: [AirPort configd plug-in is slow(828 ms)] [com.apple.bluetooth.sleep is slow(1914 ms)]           
2023-07-26 22:04:46 -0400 Assertions            PID 357(powerd) Created UserIsActive "com.apple.powermanagement.kernel.useractive AppleM68Buttons:sleepDisplayTickle kIOMessageSystemWillSleep" 00:00:00  id:0x0x9000088d4 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 426(mDNSResponder) Created MaintenanceWake "mDNSResponder:maintenance" 00:00:00  id:0x0xd000088d6 [System: PrevIdle DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 426(mDNSResponder) Released MaintenanceWake "mDNSResponder:maintenance" 00:00:00  id:0x0xd000088d6 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context534.preventuseridledisplaysleep" 00:13:21  id:0x0x50000881f [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context534.preventuseridlesleep" 00:13:21  id:0x0x100008816 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context542.preventuseridledisplaysleep" 00:13:21  id:0x0x50000883e [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context542.preventuseridlesleep" 00:13:21  id:0x0x10000883c [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context539.preventuseridledisplaysleep" 00:13:21  id:0x0x500008833 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context539.preventuseridlesleep" 00:13:21  id:0x0x10000882d [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context535.preventuseridledisplaysleep" 00:13:21  id:0x0x500008830 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context535.preventuseridlesleep" 00:13:21  id:0x0x100008825 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context547.preventuseridledisplaysleep" 00:13:21  id:0x0x50000884f [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context547.preventuseridlesleep" 00:13:21  id:0x0x10000884e [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context541.preventuseridledisplaysleep" 00:13:21  id:0x0x500008838 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context541.preventuseridlesleep" 00:13:21  id:0x0x100008831 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.04720705-0000-0000-001A-0104A5462778.context.preventuseridledisplaysleep" 00:13:21  id:0x0x500008834 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.04720705-0000-0000-001A-0104A5462778.context.preventuseridlesleep" 00:13:15  id:0x0x10000882b [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context545.preventuseridledisplaysleep" 00:13:21  id:0x0x500008848 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context545.preventuseridlesleep" 00:13:21  id:0x0x100008846 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context544.preventuseridledisplaysleep" 00:13:21  id:0x0x500008843 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context544.preventuseridlesleep" 00:13:21  id:0x0x100008842 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context540.preventuseridledisplaysleep" 00:13:21  id:0x0x500008837 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context540.preventuseridlesleep" 00:13:21  id:0x0x10000882f [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context546.preventuseridledisplaysleep" 00:13:21  id:0x0x50000884b [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context546.preventuseridlesleep" 00:13:21  id:0x0x10000884a [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context543.preventuseridledisplaysleep" 00:13:21  id:0x0x50000883f [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context543.preventuseridlesleep" 00:13:21  id:0x0x10000883d [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context548.preventuseridledisplaysleep" 00:13:21  id:0x0x500008853 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context548.preventuseridlesleep" 00:13:21  id:0x0x100008852 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context536.preventuseridledisplaysleep" 00:13:21  id:0x0x500008832 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context536.preventuseridlesleep" 00:13:21  id:0x0x100008826 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context549.preventuseridledisplaysleep" 00:13:21  id:0x0x500008857 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context549.preventuseridlesleep" 00:13:21  id:0x0x100008856 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context538.preventuseridledisplaysleep" 00:13:21  id:0x0x500008836 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context538.preventuseridlesleep" 00:13:21  id:0x0x10000882e [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context560.preventuseridledisplaysleep" 00:13:19  id:0x0x50000888c [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context560.preventuseridlesleep" 00:13:19  id:0x0x100008889 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context562.preventuseridledisplaysleep" 00:13:19  id:0x0x500008892 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context562.preventuseridlesleep" 00:13:19  id:0x0x100008891 [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context561.preventuseridledisplaysleep" 00:13:19  id:0x0x50000888e [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleSystemSleep "com.apple.audio.context561.preventuseridlesleep" 00:13:19  id:0x0x10000888d [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Assertions            PID 423(coreaudiod) Released PreventUserIdleDisplaySleep "com.apple.audio.context550.preventuseridledisplaysleep" 00:13:20  id:0x0x50000885b [System: PrevIdle DeclUser kDisp]          
2023-07-26 22:04:46 -0400 Notification          Display is turned on                                                                  
2023-07-26 22:04:46 -0400 Assertions            PID 413(WindowServer) Created PreventSystemSleep "com.apple.WindowServer.PUIDS" 00:00:00  id:0x0x7000088d7 [System: PrevIdle PrevSleep DeclUser kCPU kDisp]          
2023-07-26 22:04:47 -0400 Wake                  Wake from Deep Idle [CDNVA] : due to SMC.OutboxNotEmpty smc.70070000 lid/HID Activity Using AC (Charge:100%) 1349 secs 
2023-07-26 22:04:47 -0400 WakeDetails           DriverReason:SMC.OutboxNotEmpty - DriverDetails:                           
DriverReason:smc.70070000 - DriverDetails:                                 
DriverReason:lid - DriverDetails:                                          
2023-07-26 22:04:47 -0400 HibernateStats        hibmode=3 standbydelaylow=0 standbydelayhigh=0                                        184           
2023-07-26 22:04:47 -0400 WakeTime              WakeTime: 0.779 sec                                                                   
2023-07-26 22:04:47 -0400 Kernel Client Acks    Delays to Sleep notifications: [HP Device Monito is slow(3063 ms)] [AppleH13CamIn driver is slow(msg: SetState to 1)(994 ms)] [AppleH13CamIn driver is slow(msg: SetState to 0)(267 ms)] [IOSCSIPeripheralDeviceType00 driver is slow(msg: SetState to 2)(514 ms)] [IOSCSIPeripheralDeviceType00 driver is slow(msg: SetState to 4)(496 ms)] [laclient timed out(30000 ms)] [AppleBCMWLANCore driver is slow(msg: SetState to 0)(61 ms)] [IOSCSIPeripheralDeviceType00 driver is slow(msg: SetState to 0)(514 ms)] [com_apple_driver_AppleUSBMassStorageInterfaceNub driver is slow(msg: SetState to 0)(524 ms)] 
2023-07-26 22:04:47 -0400 Kernel Client Acks    Delays to Wake notifications: [RTBuddyV2 driver is slow(msg: SetState to 2)(101 ms)] [AppleMultiFunctionManager driver is slow(msg: SetState to 1)(115 ms)] [AppleConvergedIPCOLYBTControl driver is slow(msg: SetState to 1)(114 ms)] [usb-drd0-port-ss driver is slow(msg: SetState to 3)(128 ms)] [usb-drd0-port-ss driver is slow(msg: DidChangeState to 3)(93 ms)] [AppleBCMWLANCore driver is slow(msg: SetState to 1)(71 ms)] [IOUSBMassStorageDriverNub driver is slow(msg: SetState to 1)(217 ms)] [AppleUSB20HubPort driver is slow(msg: SetState to 3)(135 ms)] [AppleUSB30HubPort driver is slow(msg: SetState to 3)(135 ms)] [AppleUSB30HubPort driver is slow(msg: SetState to 3)(133 ms)] [AppleUSB30HubPort driver is slow(msg: SetState to 3)(234 ms)] [IOUSBMassStorageDriverNub driver is slow(msg: SetState to 1)(411 ms)] [IOSCSIPeripheralDeviceType00 driver is slow(msg: SetState to 3)(497 ms)] [IOSCSIPeripheralDeviceType05 driver is slow(msg: SetState to 4)(497 ms)]           
2023-07-26 22:04:47 -0400 Assertions            PID 357(powerd) Created InternalPreventSleep "com.apple.powermanagement.acwakelinger" 00:00:00  id:0x0xd0000892b [System: PrevIdle PrevSleep DeclUser SRPrevSleep kCPU kDisp]          
2023-07-26 22:04:47 -0400 Assertions            PID 413(WindowServer) Released PreventSystemSleep "com.apple.WindowServer.PUIDS" 00:00:00  id:0x0x7000088d7 [System: PrevIdle DeclUser SRPrevSleep kCPU kDisp]          
5
  • Can you bypass the J5 Hub? Get a quality USB-C to HDMI Adapter and go from your Mac directly to the display. I'm thinking that the Hub periodically wakes (Power Nap) and triggers a HDMI signal to go high causing your display to turn on. Let's see what happens if we bypass the J5 Hub.
    – Allan
    Aug 22, 2023 at 18:39
  • I'm using DisplayPort, not HDMI, is that relevant? Anyway, I've ordered a UDB-C to HDMI cable. I've been using this hub for several years with no problems, I wonder what changed. This isn't the first time I've gone away with the MacBook.
    – Barmar
    Aug 22, 2023 at 19:57
  • DisplayPort is a much better and more stable connection. Most folks use HDMI - sorry for making that assumption. Are you going from the J5 to the monitor via DP? Can you try going directly?
    – Allan
    Aug 22, 2023 at 23:12
  • Sorry I falied to mention it in the question. The HDMI adapter is arriving today, I'll see how that goes. If there are problems I'll order a DP adapter.
    – Barmar
    Aug 23, 2023 at 14:15
  • I connected it directly with the USB-C to HDMI adapter yesterday. So far I haven't had any repeats of this problem, so please post that as an answer. Curiously, I tried connecting the display to the HDMI port of the hub instead of DisplayPort, and the Mac doesn't detect the display at all.
    – Barmar
    Aug 24, 2023 at 19:17

1 Answer 1

0
+200

I have a MacBook Pro M1 connected to an external display through a J5Create USB hub. I have the MacBook set to put the display to sleep when idle... But lately something has changed. After a few minutes (once it was less than 5 minutes, another was more than 10) the external display comes back on and stays on.

Connect monitor directly to diagnose....

The way to diagnose this is to eliminate the USB Hub (J5 Create in this instance but applies universally) from this equation. To do this, connect the monitor directly from the Mac USB/Thunderbolt port to the monitor using either:

The signal on the MacBook is natively a DisplayPort signal so it's best to keep things as is and not convert. However, going to HDMI is not an issue especially if you use an active adapter that actually recreates the signal rather than just reorder the signal pins.

I connected it directly with the USB-C to HDMI adapter yesterday. So far I haven't had any repeats of this problem...I tried connecting the display to the HDMI port of the hub instead of DisplayPort, and the Mac doesn't detect the display at all.

This indicates an issue with the USB Hub. Many manufacturers use inferior chipsets to save on manufacturing costs. Based on the symptoms you described, it sounds like the hub is keeping a data line (to the monitor) high. This, in turn causes the monitor to "sense" that it needs to wake up when in actuality, it doesn't need to. A poorly implemented USB controller could keep voltage on a USB port regardless if the host port is in power save mode.

Since connecting the monitor directly, bypassing the USB Hub, causes the monitor to work correctly, it's safe to say that the J5Create hub is causing the issue.

8
  • I've been using this hub for several years (ever since I got the MacBook) without any similar problems. It only started a few weeks ago.
    – Barmar
    Aug 24, 2023 at 20:01
  • BTW, the monitor still seems to be in standby mode when this happens -- the power LED is amber, not blue.
    – Barmar
    Aug 24, 2023 at 20:01
  • Did you do a firmware update on the J5? The hub could also have failed. It's tough to diagnose down to that level over the internet.
    – Allan
    Aug 24, 2023 at 20:02
  • For me amber is "standby" and blue is "on" (Dell monitors) I don't know if that's standard across all monitors but it should be in standby if your Mac is asleep.
    – Allan
    Aug 24, 2023 at 20:03
  • Don't know if it's standard, but my Acer is the same. My point is that it's in standby whether it's completely off or glowing black.
    – Barmar
    Aug 24, 2023 at 20:06

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