AW3420DW not detected as G-Sync?

I have an AW3420DW monitor which supposed to be G-Sync, but in the settings I see only the checkbox about forcing G-Sync compatible.

And if unchecked then for example there is no option about G-Sync indicator in OpenGL Settings.

PopOS (Ubuntu) 20.04, 458.38 driver.

It is recognized ad Gsync, otherwise you would’nt have that checkbox in nvidia-settings.
There are 3 kind of Gsync monitors:

Yours is not in the list of gsync-compatible:

Thus not verified by nvidia.
Of course the indicator option disappears as soon you disable gsync.
The real question is, if you enable the indicator, does it show gsync or normal (while gameplay).

The AW3420DW is a real G-Sync monitor.
Do you use any kind of converter?
Please run nvidia-bug-report.sh as root and attach the resulting nvidia-bug-report.log.gz file to your post.

oh right… I missed the entry in the list… my fault.

No, just a DP cable.

nvidia-bug-report.log.gz (791.9 KB)

Nothing obvious visible.
Does it work if you disconnect the second monitor?
If not, please create a file
/etc/X11/xorg.conf.d/10-nvidia-modedebug.conf
with contents

Section "OutputClass"
    Identifier "nvidia-modedebug"
    MatchDriver "nvidia-drm"
    Option "ModeDebug" "true"
EndSection

and reboot. Afterwards, please create a new nvidia-bug-report.log

Is it enough to disable via xrandr --off?

nvidia-bug-report.log.gz (444.3 KB)

There is this occasionally in the log:
NVRM: Xid (PCI:0000:01:00): 31, pid=106462, Ch 00000086, intr 10000000. MMU Fault: ENGINE GRAPHICS GPCCLIENT_T1_1 faulted @ 0x0_00000000. Fault is of type FAULT_PDE ACCESS_TYPE_READ

Bug tracked here:

But I don’t know if that could be related.

Unfortunately, Nvidia cut the G-Sync detection info from ModeDebug, so there’s no real info to get from the logs.
Better try disconnecting the second monitor completely (though this should work with it connected).

Sounds like it should be a bug report then? :)

I tried to boot Windows and it was detected as “G-Sync capable” there, so I guess the issue is just in Linux driver.

Yes, I guess G-Sync can be considered broken on Linux with current drivers/kernels. Also, the limited mode-debug doesn’t give the slightest hint.
https://forums.developer.nvidia.com/t/440-64-ubuntu-18-04-no-g-sync/115376