Optimum resolution for Dell monitor
I have a Dell P4317Q monitor that, except for the lack of sound control, works fine with my MacBook Pro 15" (2017). At least it did, until today.
This morning when I plugged it in, my Mac decided that the highest resolution it could use was 1080. Before this, I was always able to use it at its full 2160.
Things that do not help:
Rebooting my Mac
Unplugging the monitor from the wall
Unplugging the monitor from the Mac
Turning the monitor on and off
Holding in option when selecting the resolution in the Settings->Display menu
What happened, and how do I fix it?
I'm running Big Sur.
MacBook Pro 15″, macOS 10.13