pin old kernel for tablets

flake.lock

@@ -266,6 +266,22 @@
         "type": "github"
       }
     },
+    "nixos-hardware": {
+      "locked": {
+        "lastModified": 1764440730,
+        "narHash": "sha256-ZlJTNLUKQRANlLDomuRWLBCH5792x+6XUJ4YdFRjtO4=",
+        "owner": "NixOS",
+        "repo": "nixos-hardware",
+        "rev": "9154f4569b6cdfd3c595851a6ba51bfaa472d9f3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "master",
+        "repo": "nixos-hardware",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1732981179,
@@ -282,6 +298,22 @@
         "type": "github"
       }
     },
+    "nixpkgs-old-kernel": {
+      "locked": {
+        "lastModified": 1764560356,
+        "narHash": "sha256-M5aFEFPppI4UhdOxwdmceJ9bDJC4T6C6CzCK1E2FZyo=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6c8f0cca84510cc79e09ea99a299c9bc17d03cb6",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "nixpkgs_2": {
       "locked": {
         "lastModified": 1764522689,
@@ -359,7 +391,9 @@
         "disko": "disko",
         "home-manager": "home-manager",
         "lazyvim-nixvim": "lazyvim-nixvim",
-        "nixpkgs": "nixpkgs_2"
+        "nixos-hardware": "nixos-hardware",
+        "nixpkgs": "nixpkgs_2",
+        "nixpkgs-old-kernel": "nixpkgs-old-kernel"
       }
     },
     "systems": {

flake.nix

@@ -1,6 +1,7 @@
 {
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
+    nixpkgs-old-kernel.url = "github:NixOS/nixpkgs/nixos-25.05";
     home-manager = {
       url = "github:nix-community/home-manager/release-25.11";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -12,7 +13,7 @@
     nixos-hardware.url = "github:NixOS/nixos-hardware/master";
     lazyvim-nixvim.url = "github:azuwis/lazyvim-nixvim";
   };
-  outputs = inputs@{ self, nixpkgs, home-manager, disko, lazyvim-nixvim, nixos-hardware,... }: {
+  outputs = inputs@{ self, nixpkgs, nixpkgs-old-kernel, home-manager, disko, lazyvim-nixvim, nixos-hardware,... }: {
     nixosConfigurations = import ./hosts { inherit inputs; };
   };
 }

hosts/default.nix

@@ -1,4 +1,4 @@
-{ inputs }:
+{ inputs, ... }:
 
 let
   nixpkgs      = inputs.nixpkgs;

hosts/hacks/rust-fix.patch

@@ -1,12 +0,0 @@
-diff --recursive -u linux-6.15.9.orig/scripts/generate_rust_target.rs linux-6.15.9/scripts/generate_rust_target.rs
---- linux-6.15.9.orig/scripts/generate_rust_target.rs	2025-08-01 10:51:29.000000000 +0200
-+++ linux-6.15.9/scripts/generate_rust_target.rs	2025-11-29 12:30:54.792372738 +0100
-@@ -225,7 +225,7 @@
-         ts.push("features", features);
-         ts.push("llvm-target", "x86_64-linux-gnu");
-         ts.push("supported-sanitizers", ["kcfi", "kernel-address"]);
--        ts.push("target-pointer-width", "64");
-+        ts.push("target-pointer-width", 64);
-     } else if cfg.has("X86_32") {
-         // This only works on UML, as i386 otherwise needs regparm support in rustc
-         if !cfg.has("UML") {

hosts/nix-surface.nix

@@ -1,4 +1,11 @@
-{ config, lib, modulesPath, ... }:
+{ config, lib, pkgs, inputs, modulesPath, ... }:
+let
+  refSystem = inputs.nixpkgs-old-kernel.lib.nixosSystem {
+    system = pkgs.system;
+    modules = [ inputs.nixos-hardware.nixosModules.microsoft-surface-go ];
+  };
+  refKernelPackages = refSystem.config.boot.kernelPackages;
+in 
 {
   imports =
     [ (modulesPath + "/installer/scan/not-detected.nix")
@@ -16,10 +23,7 @@
     "rd.systemd.show_status=auto"
   ];
 
-  boot.kernelPatches = [{
-    name = "rust-1.91-fix";
-    patch = ./hacks/rust-fix.patch;
-  }];
+  boot.kernelPackages = lib.mkForce refKernelPackages;
 
   disko.devices.disk.main.content.partitions.swap.size = "8G";
   nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";