add intel graphics hardware accel

lnf/configuration.nix

@@ -10,6 +10,31 @@
   boot.loader.grub.enable = true;
   boot.loader.grub.device = "/dev/vda";
   boot.loader.grub.useOSProber = true;
+  
+  services.xserver.videoDrivers = [ "modesetting" ];
+
+  hardware.graphics = {
+    enable = true;
+    extraPackages = with pkgs; [
+      # Required for modern Intel GPUs (Xe iGPU and ARC)
+      intel-media-driver     # VA-API (iHD) userspace
+      vpl-gpu-rt             # oneVPL (QSV) runtime
+
+      # Optional (compute / tooling):
+      intel-compute-runtime  # OpenCL (NEO) + Level Zero for Arc/Xe
+      # NOTE: 'intel-ocl' also exists as a legacy package; not recommended for Arc/Xe.
+      # libvdpau-va-gl       # Only if you must run VDPAU-only apps
+    ];
+  };
+
+  environment.sessionVariables = {
+    LIBVA_DRIVER_NAME = "iHD";     # Prefer the modern iHD backend
+    # VDPAU_DRIVER = "va_gl";      # Only if using libvdpau-va-gl
+  };
+
+  # May help if FFmpeg/VAAPI/QSV init fails (esp. on Arc with i915):
+  hardware.enableRedistributableFirmware = true;
+  boot.kernelParams = [ "i915.enable_guc=3" ];
 
   networking.hostName = "nixos-lnf";
   networking.wireless.enable = true;