Screen flicker with Odyssey G9 + 6800xt

[Sid]

Hi fam. I was just given (yes, given, in an extremely fortunate stroke of luck) a Samsung Odyssey G9 (LC49G95TSSNXZA) 5120x1440@240Hz, 32:9. I am using a 6800xt GPU w/ DP1.4 cable.

It works totally fine at 120Hz but switching to 240Hz causes instant and extreme screen flicker/static:

Some steps I have tried already:

• Adding custom resolution with crh. These custom settings are not reflected in the settings:

• Verified display is using the latest firmware from Samsung
• Disable VRR, both in the display and in GNOME settings
• Use LACT to manually change the power profile to COMPUTE
• Applying this custom EDID that seems to be created for this exact problem, but I’m really not sure how to apply it since it seems to be made for Arch and the .bin file I downloaded doesn’t seem to be visible by crh(see image above again). Tried to just paste the .bin file into /usr/lib/firmware/edid but it said I was not permitted, presumably due to immutable filesystem?

Thanks in advance.

[Sp4rkR4t]

A DP1.4 cable can handle 4k@144 and your res is roughly similar so I doubt it would really be able to cope with 240hz.

[Sid]

Uhhhh I mean, that’s the spec of the ports on the monitor. If that were true it would be impossible to run the monitor at its given resolution/hz

[dallebrinaar]

I’m just grasping at straws here. But, is Display Screen Compression (DSC) turned on for the monitor? From what I can see, DisplayPort 1.4 can handle the bandwidth for your resolution and refresh rate only with DSC on. If it’s already on, I’d suggest trying different cables: (EDIT: oops, I’m pretty sure HDMI 2.1 is not available under linux) [strike] HDMI 2.1 if you have it and there are appropriate connectors [/strike], or another DisplayPort 1.4 cable.

[Sid]

As far as I know, DSC is not something that needs to be enabled. It runs automatically. I don’t see a setting for it in the monitor OSD.

Switching to HDMI drops the max to 60Hz

[Sid]