Mac mini (2018) - ignoring HDMI port on 11.5.1; working for months prior
PROBLEM STATEMENT:
* Mac mini (2018) recently refusing to power-on and drive the Mac mini HDMI port.
CONFIGURATION:
- Mac mini (2018) - macOS Big Sur (11.5.1) - 64G RAM, 2TB disk, 3.2GHz 6-Core Intel Core i7
- UtechSmart 17 in 1 Quadruple Display Laptop USB C Docking Station, USB C Hub Dock 3 HDMI Adapter for MacBook&Windows (3HDMI,VGA,PD 3.0,Ethernet, SD/TF Card Reader, Audio, 5 USB Ports).
- HDMI KVM Switch 4 Port Dual Monitor Extended Display, CKL USB KVM Switch HDMI 4 in 2 Out with Audio Microphone Output and USB 2.0 Hub, PC Monitor Keyboard Mouse Switcher 4K@30Hz CKL-942HUA
- Samsung 43" TV - TU8000FXA - Smart TV - HDMI > HDMI KVM
- Samsung 43" TV - UN43JU640D - Smart TV - HDMI > UtechSmart 17
- Portable Monitoring, 16" Bluelight Eye Care Full HD 1080P HDR Monitor with Screen Projector, Dual Screen for PC/Mac/Windows/Tablet/Laptop/Xbox/Switch/Phone/SLR Camera/DVD Player - Geoyeao - Mini-HDMI > Mac mini HDMI
SYMPTOM:
- In recent weeks (maybe 2w), the 1080P monitor has been refusing to display.
- Watching the 1080P display, display dialogs indicate that nothing is on the other end of the micro-HDMI cable (nobody is home) and then a message indicating a power-savings mode.
WORKAROUNDS (which no longer work):
- Unplug the 1080P HDMI cable from the Mac mini, wait a second or two, then plug it back in. The 1080P display then gets recognized and becomes an assignable screen within Settings > Displays > Arrangement.
VERIFICATIONS:
- Does the 1080P monitor work? Yes. I've plugged it in via the UtechSmart and via the CKL dual 4K HDMI KVM and the Mac mini treats it as a monitor.
HISTORY OF THIS CONFIGURATION WORKING:
- All of these pieces came together in February of 2021 and have been operating reliably through middle of July.
- The problem with the HDMI port not being activated (interpreted cause) has become an annoyance in the last 2-3 weeks.
- Today, 2021-08-03, it reached a flat-out refusal to operate.
OS CHANGES:
- This is a work-machine; purchased in November, 2020 before the M1 came out and rebuilt from the OS up to work standards.
- OS updates are forced by work to ensure that the machine is secure, so the patching behavior is work-centric, not home-centirc.
COMMENTS ABOUT THE DIFFERENT PIECES IN PLAY:
- The Dual 4K HDMI KVM will share one 4K HDMI source, but then MIRROR the second HDMI source, so only one 4K HDMI is connected via the KVM.
- The second 4K HDMI source is connected via the UtechSmart 17 which has an HDMI connector.
- The third HDMI connector is the one on the back of the Mac mini and which (I believe) to be the source of the problem described here.
SOFTWARE IN PLAY:
- https://github.com/jakehilborn/displayplacer - Because I want my windows to return to the resolution / order / position that they are set in, I use this script to list the current configuration. That list, is actually a command line with all of the parameters to flip the KNOWN (HDMI) monitors to be pushed into a specific mode and to be ordered in the left-to-middle-to-right order at the OS level.
- This script has NO ability to make the OS talk on the HDMI port and to force the monitor to wake up.
DESIRED SOLUTION / CONFIGURATION:
- My 1080P display is my explicit meeting sharing display as I otherwise have the problem where I have a dedicated 1080P display focused solely on screen sharing (all of my meeting participants are not as heavily invested in their display equipment as I am).
- Having some way to force the OS to probe all HDMI ports rather than the auto-probe on a display disconnect / reconnect would be ideal.
BARELY TOLERABLE CONFIGURATION:
- Flipping one of my two 4K monitors down to 1080P creates artifacts of screen motion (applications sized for 4K have to be shut-down for the duration of the sharing).
- Flipping from 4K to 1080P and then back to 4K several times a day is cost-prohibitive to my productivity.
If anyone knows of any way to ask the OS what it's display probe results are so that I can forward it to Support, I'd be ecstatic!