After update from 10.15.3 to 10.15.4 external displays doesn't work via docking station

THIS!

Disabling "power nap" in both battery and power adapter mode has helped immensely! If my screen saver comes on or I put it to "sleep", all I have to do is move my mouse or type a key and things work. I no longer need to lift the lid to wake my computer and get the external monitor to connect.

Update: my previous solution (to reset SMC) proved temporary. External display disappeared again, even though I haven't used my Thunderbolt ports for anything other than connecting the display in these days. Worked for about 5 hours but then suddenly disappeared. For a moment it flickered on and off. Now it doesn't even appear again momentarily after a reboot.

I suppose I could keep resetting the SMC but hoping Apple will fix this in an update soon.

Do Apple reps ever drop into these threads and confirm they have things in hand?

I have the same issue on Macbook Pro 16" 5500m, my Asus PQ321 4k display, which is same panel as the Sharp 4k display just shows black after the10.15.4 update. The problem is that the firmware I believe is causing the issue and I have tried 10.15.5 beta 2, beta 3, downgraded to 10.15.2, 10.15.3, 10.15.4...nothing works! The firmware after its been updated it wont go back and there is no way to revert even if you go back to 10.5.3 or earlier. I tried 10 clean installs, nothing..'

I'm talking to apple care now and waiting for their engineering dept to get back to me, doubt they have a fix though :(. I've tried everything on the internet, displaylink drivers, privacy, safe boot, reinstall, smc, pram/nvram but nothing works. I'm pretty certain the firmware update from 10.5.4 broke it, if there was a way to go back I'm 99% sure it would work.

I need to use my monitor or else why do I have this $4500 machine if I cant use basic standard computer things... 10.15.5 beta 4 is out, but I haven't tried and I'm kind of so defeated if it doesn't work I'll be sad. I ordered an eGPU razer x with 5700 XT, so I'm hoping that works and actually will run the 4k 60hz scaled a lot smoother and leave the dgpu for processing.

Very frustrating...

Hello gvfx2000,

I found that usb-c to HDMI cable work with my Sharp 4K display (an old display I bought in 2014). However, the display only support 4K 30fps for HDMI so the performance is not good as DisplayPort (4K 60fps) if you need to use the monitor for graphic work. It's good for web browsing and basic text work. USB-C to DisplayPort cable does not work no matter what I tried. Hope Apple will quickly fix this problem. It's unacceptable that the newest 16 MacBook pro cannot work with an old 4K display.

Hey smoothitaway,

Yeah I have the same issue, I can run it with USB-C to HDMI at 30hz but I NEED 60hz. On my monitor if I change it to SST(single stream transport) I can get displayport to work at 30hz, so I think you should have a displayport option as well to get 30hz on displayport, but of course we need 60hz...

I can't connect to my DELL Monitor by Type-C , it's alway not get any signals ... It suck , i looked at the update of 10.15.4 , they said they "Resolves an issue where a USB-C port in your Mac may become unresponsive" but it doesn't

As above it does seem that the issues are the firmware causing some of the issues. Each Catalina release has come with firmware updates th seem to cause new and additional external monitor issues. Unfortunately there is no apparent way of going backwards. I've tried to find a way and asked on several forums without any luck. So the simple answer is wait until you get a release that works then never upgrade again unfortunately. The choice of having some new feature thats never used versus a working external monitor I know which is the best option for myself.

Just made my third attempt to solve this problem with Apple support. A 2h phone call repeating generic procedures with someone that was following some guide lines and ended up telling me to format the Mac without any guarantee of this solving the issue (I know it won't because some users already did that) or wait for the next update and fingers crossed it might fix it. When? Nobody knows.

My sound studio has my 2 months old Mac on top o my mixing desk rendering all my workflow useless.

This is just getting more and more ridiculous.

Hello gvfx2000,

I was able to reproduce this following your procedure. Thank you so much for sharing this. 60Hz via DisplayPort is so much better than 30Hz via HDMI.

We now know this method works, surely hope Apple could make a quick fix in the future update.

Cheers!

Sounds like the initial connection is getting the EDID incorrect from the monitor. Have you checked the reporting under displays that when the monitor is black and when it is on that the reports are the same? Have you compared an AGCDiagnose on the drivers when blank and when working? Is there a difference between the 2 dumps?

/System/Library/Extensions/AppleGraphicsControl.kext/Contents/MacOS/AGDCDiagnose -a > AGDCDiagnose_a.txt 2>&1

Depending on what you see it could just be that the EDID information that the MAC is getting is wrong or worse case, like myself, the drivers determine the incorrect bandwidth for a channel. However, if your lucky and the EDID data is wrong you could create an override for the display manually, or use the github edidrb program, or install switchresx and create it.

There is a great amount of discussion on resolving MAC display issues over here. Large discussions on trying to get resolutions correct etc through overriding the OS. Yes that is 94 page long thread.

I should have mentioned I'm running 10.15.1 still because I do not want to inherit any new issues. However I run an elgato3 dock with a Apple 27 inch and a LG 27inch 4k monitor. Apple only gets the 4k LG resolution correct when first connected. The 4k was shared with my home machine running win10 via a HDMI switch. However, MACos only gets and sets the correct parameters when the 4K is present at start up. If I try and switch it the MACos driver switch it to 1920x1080. If I look at AGCDiagnose its because the MACos gets the bandwidth of the channels incorrect and down grades the speed of the possible connection from HBR2 to HBR. A duplicate machine with 10.14.5 works perfectly and sets HBR2 every time irrespective. Unfortunately the EDID override will not fix this issue.

How can I know what is the correct EDID?

This is the best I could find:

╰─[:)] % sudo ioreg -l | grep IODisplayEDID
Password:
    | |   |           | | | |       "IODisplayEDID" = <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>

When I run AGCDiagnose I get a lot of info on terminal, but then again I am stuck because my monitor does not connect to the Macbook.

Can you point me to some info abou this? I already checked tonymacx86 thread, but could not find any info abou this.

Thanks

LG 24UD58 connects to MacBook pro '13 2018 occasionnaly after about an hour of connection. "Option" button + Detect Displays in System Preferences seems not work at all. Error occured after update of 17 May 2020.

The easiest way is to try switchresx as it enables an easy path to setting the overrides refresh and resolution. If you can get it to work with that then you can manually install the override or purchase it.

https://www.madrau.com/

Not sure if it's been mentioned here already as I haven't been keeping up with the discussion, but I found a fix for my Dell D6000 docking station. I read several people early on saying updating the dock's firmware might help but requires a Windows PC. I had an old Windows desktop I rarely use anymore so I hooked it up and was able to update with the D6000 Firmware Update Utility (https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=jw5xm) in about 20 minutes. Plugged it back up to my Air running 10.15.4 and it immediately recognized my two Dell monitors and is charging the MacBook like normal. It's only been 30 minutes or so, but so far so good.

Before all this, I did download DisplayLink Manager which didn't solve any issues at the time. When I hooked the dock back up to my Air, the DisplayLink Manager needed permission for screen recording, which I granted. Not sure if this is a necessary step, but there is a note on the right side of the download page (https://www.displaylink.com/downloads/macos) talking about MacOS 10.15 issues with a link to some more info on how to unblock DisplayLink Kernel Extensions.

Thought this might help some with the same dock as it was an easy fix for me, and the DisplayLink Kernel Extension information might help others even if they aren't using a D6000 dock.