Reboots when display is connected to Ultra Dock when sleeping or shutting down

[swatchie-1]

Hi Swanux, any update coming up soon to improve on this?

[swanux]

Currently looking for possible solutions, keeping this issue open until it's resolved. So if anyone has a suggestion / idea regarding this specific problem they can post it here.

EDIT: To actually answer your question, there is no concrete ETA for it.

[swatchie-1]

Nice. I wonder why it works for T450s according to @findyy99
Here is the link.

[swanux]

Bad news. Recently I've successfully booted my T440p with the EFI for T450s (where the dock works), but sadly it doesn't work. Still the same issues with dock, even though I've just slightly modified the config for the hardware.

[swatchie-1]

Keep trying. For those who still want to use the dock and an external display, use your mini DP instead of the dock's display output. Keep your dock's display output free.

With the new Mac's update to 10.15.6, the external display seems to show up faster when using the mini DP.

[swanux]

@swatchie-1 Some news on this issue: not sleep or shutdown causes the error!
You can test it for yourself. Here is a tool, use the command line option of it to list and then disable your external monitor which is connected to the dock. After you hit enter on the disable command, your laptop will reboot (atleast mine did).
So the problem is because of the "ejection" of the external display which is a part of both the sleep and the shutdown process.
Any ideas regarding this situation?

[swatchie-1]

Hi @swanux i've tested with your disablemonitor tool. It indeed causes a reboot KP. Now you've discovered the source of the problem, lets try to overcome it.

Why don't we ask sniki if he has any idea.

[swanux]

Hi @swatchie-1 , good to hear confirmation!
Yeah, asking sniki is a good idea. If it's okay for you, I'd leave it to you as I'm on vacation now (and banned from tonymacx86 for no reason, haha). Maybe it'd boost the overall t440p development a bit if someone solves it.