How to enable Steam Play (Proton) directly in SteamOS

How-To: Enable Valve's Proton Compatibility Tool in SteamOS

As we all know, in August of 2018, Valve rebranded Steam Play and released Proton, a forked version of Wine which includes DXVK, into the Linux Steam client. This allowed users to very easily run Windows-only games, without the hassle of vanilla Wine and DXVK. Sadly however, this option to enable Proton is still non-existent within Big Picture Mode, which also affects SteamOS. While this may appear odd at first, the speculation is that this will be added in when Proton is no longer in Beta, and a possible major update to SteamOS will boast the ability to play Windows titles commercially. Perhaps that could also be a sign of new Steam Machines?

However, what about those of us who already use SteamOS? Don't worry, it's a pretty painless process to enable. With a little terminal trickery, we can turn existing Steam Machines and/or SteamOS powered computers into early prototypes of what Valve may be trying to achieve in the future, and discover some pretty shocking and exciting things under the hood. 

STEP ONE: Enable SteamOS Beta Updates

No, I don't mean opting into the Steam beta within BPM (Big Picture Mode), which can be done in the settings. But rather instead the SteamOS beta, which you have to do completely within the desktop mode. This is so you get the more recent 2.166 "brewmaster_beta" version of the underlying operating system, which includes updated NVIDIA and Mesa drivers that was released back in August last year, which Valve have sadly not yet pushed out for everyone.

First and foremost, you have to "Enable Access To The Linux Desktop", in the Interface tab in the settings menu. Then, exit to the desktop. 

To continue, you need to open a terminal emulator. You can use Gnome Terminal or Xterm. In my experience, using Gnome Terminal just hangs and never opens, so optionally find xterm within your  usr/bin folder, which is in your home folder. To make this easier in future, you might want to pin that xterm to your favorites.

Once Xterm is open type:

passwd

Which will allow you to set the root/sudo password for desktop mode. After that, enter the following consecutively:

sudo apt install steamos-beta-repo

sudo apt update

sudo apt upgrade

sudo apt dist-upgrade

Optionally, you can also type in the following commands to clean your system of now obsolete files:

sudo apt autoremove

sudo apt autoclean

Reboot the system and congratulations! You are now running SteamOS in Beta! However, we still need to enable Proton.

You might want to check to see if your system is indeed running in Beta. You need to go into the Settings menu in Big Picture Mode, enter the System tab, and on the right hand side you should see your Steam Machine's internal specifications, which down towards the bottom should list the driver version.

STEP TWO: Enable Proton Via The Standard Steam Window

Lastly, we need to enable Proton, which can only be done via the standard desktop Steam window, due to BPM missing it. To do this, exit back into desktop mode, open your terminal of choice. Now enter the following commands in order for us to restart Steam with the standard desktop window.

sudo -i -u steam

The command above gives us, the 'desktop' account, with access to control the elevated SteamOS account.

Next, we need to kill Steam and restart it. Enter the following commands:

pkill steam
steam

Steam should now show the standard update window that desktop users see upon clicking on / starting Steam. Sometimes after doing this process for the first time, Big Picture will take over. No worries, just exit and try it again and it will work. 

From the standard desktop window, we can just click on Steam in the upper left hand corner, go all the way down to the SteamPlay tab, and we can enable Proton just like standard users on other distros. 

Exit Steam and type the following command:

sudo reboot

You can now use Big Picture Mode as usual, but now with the option to install Windows only titles! SteamOS even has the ability to type in launch commands, which you can find after clicking on a game. Some games will require special commands and this is what leads me into the final section of this article.

STEP THREE: Wonder What's Next!

To conclude this article, let's revisit where I said in the introduction that we'd find some pretty shocking things going on with SteamOS.

After enabling the SteamOS Beta and Proton, I discovered that many games, such as GTA V or Slender: The Arrival, which required things such as mscorefonts or other various dependencies, along with special launch commands, worked right out of the box with minimal bugs on SteamOS! Every other distro I've tried has required extra work from the user on many titles, these included. GTA V worked near flawlessly and didn't need the fixes listed on GitHub and by other various community outlets. This was the same for Outlast 2, Slender: The Arrival, Bully Scholarship Edition, and many other Windows games I tested. To further prove SteamOS is the epicenter for Valve's Linux innovations, (as stated by a valve employee when asked about the removal of Steam Machines from the hardware tab on the Steam Store) I did a fresh install of Linux Mint 19, and sure enough, GTA V and other titles needed the listed fixes in order to work.

Hope this helps.