use jovian-nixos + fixup niri display session handling

etcnixos/common.nix

@@ -6,6 +6,7 @@
   system,
   hostname,
   inputs,
+  niri-package,
   ...
 }:
 {
@@ -33,6 +34,9 @@
 
   services.kmscon.enable = true;
 
+  # Add niri to display manager session packages
+  services.displayManager.sessionPackages = [ niri-package ];
+
   # Gamescope configuration for Steam Deck-like experience
   programs = {
     gamescope = {
@@ -45,26 +49,6 @@
     };
   };
 
-  services.greetd = {
-    enable = true;
-    settings = {
-      default_session = {
-        command = "${lib.getExe pkgs.tuigreet} --sessions /etc/xdg/wayland-sessions/ --time";
-        user = username;
-      };
-      terminal.vt = lib.mkForce 2;
-    };
-  };
-
-  environment.etc."xdg/wayland-sessions/niri-session.desktop".text = ''
-    [Desktop Entry]
-    Name=Niri Session
-    Comment=Niri Wayland compositor
-    Exec=niri-session
-    Type=Application
-    DesktopNames=niri
-  '';
-
   system.activationScripts = {
     # FIX: https://github.com/NixOS/nix/issues/2982
     "profile-channel-dummy".text = ''
@@ -97,6 +81,9 @@
     ];
   };
 
+  # allow unfree packages for jovian-nixos
+  nixpkgs.config.allowUnfree = true;
+
   # kernel options
   boot = {
     kernelPackages = pkgs.linuxPackages_latest;

etcnixos/steam.nix

@@ -25,26 +25,4 @@
     goverlay
     yad
   ];
-
-  # Create steam session script
-  environment.etc."steam-session-greetd".source = pkgs.writeShellScript "steam-session-greetd" ''
-    export STEAM_RUNTIME=1
-    export SDL_VIDEODRIVER=wayland
-    export QT_QPA_PLATFORM=wayland
-    export GDK_BACKEND=wayland
-    export XDG_CURRENT_DESKTOP=Steam
-    export XDG_SESSION_TYPE=wayland
-    exec ${pkgs.gamescope}/bin/gamescope --adaptive-sync --hdr-enabled --rt --steam -- ${pkgs.steam}/bin/steam -pipewire-dmabuf -tenfoot
-  '';
-
-  # Create system-wide session files
-  environment.etc."xdg/wayland-sessions/steam-session.desktop".text = ''
-    [Desktop Entry]
-    Name=Steam Session
-    Comment=Steam Deck-like gaming session with gamescope
-    Exec=/etc/steam-session-greetd
-    Type=Application
-    DesktopNames=steam
-  '';
-
 }

etcnixos/system-mreow.nix

@@ -34,4 +34,25 @@
   # disable framework kernel module
   # https://github.com/NixOS/nixos-hardware/issues/1330
   hardware.framework.enableKmod = false;
+
+  # Greetd display manager
+  services.greetd = {
+    enable = true;
+    settings = {
+      default_session = {
+        command = "${lib.getExe pkgs.tuigreet} --sessions /etc/xdg/wayland-sessions/ --time";
+        user = username;
+      };
+      terminal.vt = lib.mkForce 2;
+    };
+  };
+
+  environment.etc."xdg/wayland-sessions/niri-session.desktop".text = ''
+    [Desktop Entry]
+    Name=Niri Session
+    Comment=Niri Wayland compositor
+    Exec=niri-session
+    Type=Application
+    DesktopNames=niri
+  '';
 }

etcnixos/system-yarn.nix

@@ -18,6 +18,7 @@
     inputs.nixos-hardware.nixosModules.common-cpu-amd-zenpower
     inputs.impermanence.nixosModules.impermanence
     inputs.disko.nixosModules.disko
+    inputs.jovian-nixos.nixosModules.default
   ];
 
   fileSystems."/media/games" = {
@@ -58,4 +59,17 @@
   systemd.services.lactd.wantedBy = [ "multi-user.target" ];
 
   systemd.services.lactd.serviceConfig.ExecStartPre = "${lib.getExe pkgs.bash} -c \"sleep 3s\"";
+
+  jovian = {
+    devices.steamdeck.enable = false;
+    steam = {
+      enable = true;
+      autoStart = true;
+      desktopSession = "niri";
+      user = username;
+    };
+  };
+
+  # Disable gamescope from common.nix to avoid conflict with jovian-nixos
+  programs.gamescope.enable = lib.mkForce false;
 }

flake.lock

@@ -186,6 +186,27 @@
         "type": "github"
       }
     },
+    "jovian-nixos": {
+      "inputs": {
+        "nix-github-actions": "nix-github-actions",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1763640802,
+        "narHash": "sha256-TAsO9p2cF/Wm6sYWPqvC/mBzMBzG119XLB6T0XwU2NU=",
+        "owner": "Jovian-Experiments",
+        "repo": "Jovian-NixOS",
+        "rev": "4b1c28efe3b31e00c427e651b398d8251dd29812",
+        "type": "github"
+      },
+      "original": {
+        "owner": "Jovian-Experiments",
+        "repo": "Jovian-NixOS",
+        "type": "github"
+      }
+    },
     "lanzaboote": {
       "inputs": {
         "crane": "crane",
@@ -309,6 +330,28 @@
         "type": "github"
       }
     },
+    "nix-github-actions": {
+      "inputs": {
+        "nixpkgs": [
+          "jovian-nixos",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1729697500,
+        "narHash": "sha256-VFTWrbzDlZyFHHb1AlKRiD/qqCJIripXKiCSFS8fAOY=",
+        "owner": "zhaofengli",
+        "repo": "nix-github-actions",
+        "rev": "e418aeb728b6aa5ca8c5c71974e7159c2df1d8cf",
+        "type": "github"
+      },
+      "original": {
+        "owner": "zhaofengli",
+        "ref": "matrix-name",
+        "repo": "nix-github-actions",
+        "type": "github"
+      }
+    },
     "nixos-hardware": {
       "locked": {
         "lastModified": 1762847253,
@@ -371,6 +414,7 @@
         "emacs-overlay": "emacs-overlay",
         "home-manager": "home-manager",
         "impermanence": "impermanence",
+        "jovian-nixos": "jovian-nixos",
         "lanzaboote": "lanzaboote",
         "niri": "niri",
         "nix-doom-emacs-unstraightened": "nix-doom-emacs-unstraightened",

flake.nix

@@ -60,6 +60,11 @@
       url = "github:serokell/deploy-rs";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    jovian-nixos = {
+      url = "github:Jovian-Experiments/Jovian-NixOS";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs =
@@ -70,6 +75,7 @@
       nixos-hardware,
       home-manager,
       deploy-rs,
+      jovian-nixos,
       ...
     }@inputs:
     let
@@ -79,6 +85,7 @@
         "mreow"
         "yarn"
       ];
+      niri-package = inputs.niri.packages.${system}.niri-unstable;
     in
     {
       formatter.${system} = nixpkgs.legacyPackages.${system}.nixfmt-rfc-style;
@@ -93,6 +100,7 @@
                 inputs
                 username
                 hostname
+                niri-package
                 ;
             };
             modules = [
@@ -103,7 +111,7 @@
                   # home-manager.useGlobalPkgs = true;
                   home-manager.useUserPackages = true;
                   home-manager.extraSpecialArgs = {
-                    inherit inputs hostname username;
+                    inherit inputs hostname username niri-package;
                     homeDirectory = "/home/${username}";
                     stateVersion = config.system.stateVersion;
                   };

home-manager/progs/niri.nix

@@ -3,6 +3,7 @@
   pkgs,
   lib,
   inputs,
+  niri-package,
   ...
 }:
 let
@@ -22,7 +23,7 @@ in
   ];
 
   programs.niri = {
-    package = pkgs.niri-unstable;
+    package = niri-package;
     settings = {
       prefer-no-csd = true;