External Monitor Display Issues - Are you using Clamshell Mode?

[af22]

I'm plagued with External Monitor Display issues as reported by others in this thread on my M1 MBP:
- Inconsistent waking of the External Monitor Display
- Resolution of the External Monitor Display being changed randomly shortly after Display is on.

I've been reading through the forums trying to test all the different ideas. Changing cables from HDMI/DP/USBC/Thunderport Hub. To switching my monitor from DP 1.4->1.2.

I wanted to start a poll to see if people are having issues with using the laptop in both clamshell mode as well as extended mode to help narrow it down.

 

[guitarguy316]

I'm in clamshell mode on MBA using the official Apple AV adapter. I scale the display on my LG UL600 4K monitor so it's not too small. It simply will not remember the resolution setting, whether I let it go to sleep or just walk away for a bit when the screen turns off.

I also have an issue where the tint will be yellow, but unplugging and plugging the hub back in will resolve it.

 

[af22]

I switched to using Extended Mode instead of Clamshell Mode. I think it's better. But I still did experience the resolution changing. But now, i can close and reopen the laptop and it will try again.

 

[Fair Witness]

I use both an M1 Air and M1 MBP in clamshell mode, I was using an older 5K Dell display but there are issues with that (it won't detect the resolution unless you do a "rotation trick", and it also periodically blacks out for a second or two) so I bought an LG 5K monitor instead. I haven't seen any issues with waking the LG 5K monitor other than sometimes it takes about 5-7 seconds to wake. I can keep the laptop closed and asleep overnight and immediately plug it into the monitor and it works fine. I also leave the M1 MBP plugged in for days at a time and periodically sleep/wake it all while in clamshell mode, everything is fine (there is, on occasion a weird graphical glitch on the LG 5K after waking, but that is a known issue and fixed by sleeping and re-awakening to wipe away the graphical glitch).

I have a feeling that some monitors like the LG 5K get a little more attention from Apple and work more consistently, and that other monitors will start to behave more consistently as more updates are made to macOS as time goes on.

 

[jdb8167]

I haven't experienced many problems since I switched to using a USB-C hub with Display Port output. But I run in clamshell mode since I have a vertical stand that means I use less desk space. I'm running the latest 11.2 RC2 and I hope it completely eliminates the external monitor problems. I should probably test without the hub to see.

Edit: So testing on Big Sur 11.2RC2 with a USB-C to Display Port cable directly, the 4K monitor does not wake after sleep unless I explicitly turn off the monitor, unplug the Display Port cable, turn on the monitor and then plug the DP cable back in. So far that consistently gives me a display. That is better than the last time I tried using the USB-C->DP cable on 11.0.1 which rarely worked no matter what I did. But it is still not great. Luckily, I'm just going to go back to the USB-C hub that solves that issue for me.