Mesa Lands Option That Can Help XWayland-Based Gaming On The Steam Deck

[shmerl]

Plagman said that Wayland is better because of the lower overhead. But the games will run mostly on XWayland.

Why would games need XWayland unless it's some legacy games built with dependency on X? More recent one can be using SDL or anything that can work with Wayland without X?

The only major hold out are of course Wine / Proton games, but Wine has some progress with Wayland support too?

[blacknova]

I'm not sure that just updating SDL to work with Wayland would be enough for most games, unless they use some windowing system agnostic GL/Vulkan initialization. AFIAK if game uses SDL for window initialization, fullscreen management, etc but uses GLX for GL initialization, it doesn't matter that SDL support wayland since GLX do not support wayland at all.

[evil_core]

I'm 99% sure Steam Deck will run on top of Xorg, and lots of users will actually install Windows on it (Valve said Windows would be fully supported) because there will be close to zero compatibility issues and no performance loss due to API translation.

What does it mean 'a lot'. Maybe even 2-5% of SteamDeck's users will install Windows on it out of curiosity(or other requirements. But don't expect that more than 0.5%-2% of it's userbase will run Windows on it daily, because experience will be subpar in comparison to custom ArchLinux spinoff they are testing and polishing for it.

About Xorg vs Wayland it doesn't matter what will be shipped on release. Valve invested much resources over the years into wayland and xwayland, KDE Plasma and it's own wayland compositor (called gamescope).
But because KDE Plasma works better on Xorg currently, and what's more important SDL1 and older releases of SDL2 has subpar performance on Wayland, they will ship SteamDeck with X11 with 99% proability. But they will switch to Wayland in future(when decided it's ready), because Xorg is limiting what can be done, especially for new VR equipment that they want to focus and ship later, after SteamDeck's release.


SDL is heavily working on SDL1->SDL2 translation layer that works in 99% of cases, providing way better performance than SDL1 native(especially on Wayland), but because of game devs used inappropriately RGBA surfaces, game rendering is broken with compositors supporting alpha channel.
You can test it by installing sdl2_compat12-git and lib32-sdl2_compat12-git form ArchLinux's AUR and export env vars:
for 64bit apps:
export SDL_VIDEODRIVER=wayland
export SDL_DYNAMIC_API=/usr/lib64/libSDL2.so

for 32bit apps:
export SDL_VIDEODRIVER=wayland
export SDL_DYNAMIC_API=/usr/lib32/libSDL2.so


Valve or Gabe Newel never stated that Windows installation (or 3rd party shops) installation will be SUPPORTED (if you know what it means), but that users are allowed to install anything they want on it (but they have to deal with problems related to it, on their own).
It's the stupid news outlets that makes such claims, with some of them evem stating that SteamDeck will be shipped with Windows with custom Steam client.

The fact is that SteamDeck is generic x86_64/UEFI AMD/RDNA2 machine, sharing hardware with laptop SoCs, so drivers are already tested on Windows. There is even one or two guys in Steam testing SteamDeck on Windows.
So while AMD SoC portion should work equally good on both Windows and Linux, the devil lies in SteamInput. They are mostly testing it with Linux/KDE Plasma and SteamInput/SDL/SDL2 games, so don't expect it to be do polished on other platforms.
And SteamDeck's advanced input capabilities are one of the most interesting parts (in-line with gaming performance) of this console.

[akuhtr]

I'm 99% sure Steam Deck will run on top of Xorg, and lots of users will actually install Windows on it (Valve said Windows would be fully supported) because there will be close to zero compatibility issues and no performance loss due to API translation.

It has only 16GB RAM for CPU and GPU. So i don't think that performance loss due to API translation is more relevant that performance loss due to
windows uses more memory for itself :-)

[Petteri]

So, XWayland it is - it's quite unexpected but maybe maybe something about Wayland works better for games.

Using wayland is quite necessary because it allows the compositor to be in full control of games. With x11 games can easily mess up the environment (grab input, modify display settings etc.).

[evasb]

So, XWayland it is - it's quite unexpected but maybe maybe something about Wayland works better for games.

Plagman said that Wayland is better because of the lower overhead. But the games will run mostly on XWayland.

Seems like they'll use Xorg for the desktop session, tho.

[birdie]

Literally all of their marketing material - and in-use pictures and videos from when media has had hands on - show it running on Wayland. (you can see some of the remaining bugs and the placeholder XWayland icon in the tray when they show desktop mode)

I wouldn't at all be surprised if SteamOS 3 ships without an X server entirely, and just supports XWayland.

So, XWayland it is - it's quite unexpected but maybe maybe something about Wayland works better for games.

[bple2137]

I'm 99% sure Steam Deck will run on top of Xorg, and lots of users will actually install Windows on it (Valve said Windows would be fully supported) because there will be close to zero compatibility issues and no performance loss due to API translation.

AFAIK, by default games launched from the console-like UI will run within the Gamescope compositor, so XWayland. When it comes to the desktop mode, they want to go Wayland (I saw a comment by said Valve developer who made Gamescope), but that depends on what shape Plasma will be in. If there will be some remaining issues, they'll use X11 session at least for some time, but they might eventually switch the default session later on. I tested Plasma on Wayland and while not perfect, it is definitely getting its robustness. Especially that KDE presented PoC around KWin reconnecting to running clients while crashing/being killed.

[Ananace]

I'm 99% sure Steam Deck will run on top of Xorg, and lots of users will actually install Windows on it (Valve said Windows would be fully supported) because there will be close to zero compatibility issues and no performance loss due to API translation.

Literally all of their marketing material - and in-use pictures and videos from when media has had hands on - show it running on Wayland. (you can see some of the remaining bugs and the placeholder XWayland icon in the tray when they show desktop mode)

I wouldn't at all be surprised if SteamOS 3 ships without an X server entirely, and just supports XWayland.

[Sunderland93]

It will run on top of Gamescope https://github.com/Plagman/gamescope