M1 mac mini display keeps losing scaling

Okay, those sound like pretty serious problems to me. I haven’t experienced anything like that, but those problems would be very frustrating to me as well.

But this forum thread is about one specific minor problem I have been having, and I would appreciate it if people would stick to discussing this problem. I’m sure there’s threads about the problems you’re having, and they also sound serious enough that you should be talking directly to Apple support and maybe returning the computer as defective.

In any case, don’t attack other users for not having the same problems as you or bot being aware of the problems you’re having.

Ah, nice, Hammerspoon looks a lot easier to deal with than Sleepwatcher. And yeah you have to change the resolution out and back, or else the display system doesn't think there's any changes to apply (which is probably also why the manual System Preferences fix requires changing the scaling to something else before changing it back too).

Possibly, and issues like these are why I was hesitant to jump over to Apple Silicon so quickly since all first-gen Apple machines have problems like these. But I was due for an upgrade and didn't want to be stuck on Intel.

My monitor is connected directly via HDMI but I've also had issues with my Thunderbolt dock disconnecting on sleep, which causes the OS to complain about unsafely disconnecting my Time Machine volume (which is connected via that dock). I haven't had any trouble with the USB-A ports, though, or with my directly-USB-C-connected NVMe drive.

The id:xxxx-xxxx should be replaced with the ID of your monitor, which you can get by running "displayplacer list" from the command line. If you only have one monitor you can leave the entire id:xxx-xxxx-xxxx off.

After starting up Hammerspoon you shoul dget a little hammer icon in your menu. Click on that and select "open config," then copy-paste the code into it. Then you'll need to open up Terminal and type "displayplacer list" and that'll give you the ID to put into the Hammerspoon configuration. For example, when I type "displayplacer list" it tells me (on the very last line)

displayplacer "id:98AD201D-167F-2937-3D19-FC1626C9B248 res:2560x1440 hz:60 color_depth:7 scaling:on origin:(0,0) degree:0" "id:1D8AB08D-7B12-48C9-0857-D6964E3302DB res:1920x1080 hz:60 color_depth:8 scaling:off origin:(2560,-60) degree:0"

so my screen ID is id:98AD201D-167F-2937-3D19-FC1626C9B248, so my resulting Hammerspoon config says:

displayWatcher = hs.caffeinate.watcher.new(function (eventType)
    for k,v in pairs(hs.caffeinate.watcher) do
        if eventType == v then
            print("Got display event: " .. k)
            break
        end
    end

    -- https://discussions.apple.com/thread/252282046?answerId=254547027022#254547027022
    if (eventType == hs.caffeinate.watcher.screensDidWake) then
        print("Refreshing screen resolution")
        hs.execute("/opt/homebrew/bin/displayplacer 'id:98AD201D-167F-2937-3D19-FC1626C9B248 res:3840x2160'")
        hs.execute("/opt/homebrew/bin/displayplacer 'id:98AD201D-167F-2937-3D19-FC1626C9B248 res:2560x1440'")
    end
end)
displayWatcher:start()

You can also make sure that displayplacer is working by selecting "console" from the hammerspoon menu and watch the log entries happen.

How did you install displayplacer? If you're getting "command not found" it means that it's not in your execution path. If you didn't install it using homebrew, try putting it in /usr/local/bin (which you can open in Finder by running "open /usr/local/bin" from Terminal).

Just closing the Hammerspoon window should be enough to make it run, yes. Also if you open the console you can see what error is happening when it tries to run. If you put displayplacer in a different location you'll need to change the script to point to it as well. The script I provided assumed you used Homebrew to install it (thus /opt/homebrew/bin) but if you put it in /usr/local/bin then it'll need to be /usr/local/bin/displayplacer.

Okay, good to know it isn't just me. I've found that power-cycling my monitor also works, so that's an okay workaround for now. Hopefully they fix this by the 11.2 final release!

Interesting. I’ve been thinking about using my thunderbolt dock to switch to displayport instead of HDMI anyway, maybe that’ll fix the issue. I’ll give that a try!