I'm on OpenSUSE with KDE Plasma and have HDR working with no problems in native application and Vulkan games, however when playing Windows games through Proton, the only way I can get it to work is through gamescope.

Launching gamescope for each game works but, from what I'm understanding, Steam expects an x11 window for the overlay to work, so it won't open and this also breaks controller remapping through Steam input (which I often need).
My current solution is to open a new tty session and run Steam inside gamescope (which is similar to how it works on SteamOS) there.
Is there a cleaner solution now, as what I'm doing now can a bit janky with some things?

Steam Overlay works fine on Wayland if that's your question

HDR is great for TV/movies but kinda sucks for gaming anyway.

Most monitors are pretty shit at displaying HDR so it's a common sentiment. The differences are massive (and hard to come back from) on an OLED.

I have a really nice OLED monitor. But most computers display things in a pretty simple colour pallet. HDR just makes everything look washed out.

Use Proton-GE! It has fixes to make the overlay work under Wayland.

I have been playing in HDR with a Steam Controller (which needs the overlay) for a while and it works perfectly.

This. You can use something like ProtonPlus (available as a flatpak/on Discover) to install/update ProtonGE if you're feeling lazy, and can set the default compatibility layer in steam settings so you don't have to adjust it for every game

Also, fellow OpenSUSE+KDE user here :)

If it looks washed out, it's probably trying to display HDR without HDR being enabled properly. First of all, it requires Gamescope with the --hdr-enabled flag, plus it has to be enabled in the system and in the game, and it may also require some other environment variables.

It really needs to be simplified.

I basically only run stream big picture through gamescope now, even on desktop.

Steam doesn’t work properly with high dpi displays, so I gave up a long time ago and have embraced gamescope.

To add to this, it uses a shim vulkan layer to create a fake X11 window for the overlay to be drawn onto and sent inputs and then it translates that into Wayland.

It's a neat hack.

Wait, HDR finally works properly in Linux now? I last tried it when KDE first added support and had to go back to Windows for HDR gaming and videos because it simply did not work. Does this mean that RTX HDR works too now? It's really useful for YouTube and games that don't have native HDR support. Please say yes, I am so done with Windows.

Didn't know that! Last time I tried it had the same issues as normal proton, I think. Now just setting PROTON_ENABLE_WAYLAND works. Thanks.

Yea, it works pretty well. I've mostly used it for games, but firefox recently added support for HDR video and it seems to work with no issues. mpv I think has had HDR for quite a bit.
I'm not sure what RTX HDR does, as I only used an AMD card with my HDR display, but there are Reshade shaders that should implement something similar and there's RenoDX (a Reshade addon) which patches games to retrofit real HDR. mpv should have something similar, but I don't think there's anything for YouTube.

Edit: mpv's inverse tonemapping does work for YouTube videos, if you are OK with playing them outside the browser.

If it's washed out, it's either that there's a mismatch in pixel format, like u/scutiger was saying or you might be used to oversaturated sRGB, as by default displays are set to stretch the input to their entire range (which if it's HDR should be close to DCI-P3). sRGB colors shouldn't look different when displayed in HDR, unless something is misconfigured.

I just hate getting blinded by the incredibly bright brights. I stick to SDR for that reason alone.