FWIW, this bug caused G-SYNC to not work in games for me (the G-SYNC indicator said NORMAL instead of G-SYNC), while nvidia-settings reported G-SYNC was active. Using the kernel parameter resolved this issue and also the "unknown display" went away.
However, this must be caused by a recent change to my system because G-SYNC was working fine before without using the kernel param. Unfortunately, I did not find out yet which change exactly caused G-SYNC to stop working.
FWIW, this bug caused G-SYNC to not work in games for me (the G-SYNC indicator said NORMAL instead of G-SYNC), while nvidia-settings reported G-SYNC was active. Using the kernel parameter resolved this issue and also the "unknown display" went away.
However, this must be caused by a recent change to my system because G-SYNC was working fine before without using the kernel param. Unfortunately, I did not find out yet which change exactly caused G-SYNC to stop working.