[mcp] Use legacy Nvidia driver.

system/hosts/mcp/hardware-configuration.nix

@@ -1,28 +1,44 @@
 # Do not modify this file!  It was generated by ‘nixos-generate-config’
 # and may be overwritten by future invocations.  Please make changes
 # to /etc/nixos/configuration.nix instead.
-{ config, lib, pkgs, modulesPath, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  modulesPath,
+  ...
+}:
 
 {
-  imports =
-    [ (modulesPath + "/installer/scan/not-detected.nix")
-    ];
+  imports = [
+    (modulesPath + "/installer/scan/not-detected.nix")
+  ];
 
-  boot.initrd.availableKernelModules = [ "nvme" "xhci_pci" "ahci" "usb_storage" "usbhid" "sd_mod" ];
+  boot.initrd.availableKernelModules = [
+    "nvme"
+    "xhci_pci"
+    "ahci"
+    "usb_storage"
+    "usbhid"
+    "sd_mod"
+  ];
   boot.initrd.kernelModules = [ ];
   boot.kernelModules = [ "kvm-amd" ];
   boot.extraModulePackages = [ ];
 
-  fileSystems."/" =
-    { device = "/dev/disk/by-uuid/123e06ed-d7a4-439b-ae37-7ff8f82ae0a7";
-      fsType = "ext4";
-    };
+  fileSystems."/" = {
+    device = "/dev/disk/by-uuid/123e06ed-d7a4-439b-ae37-7ff8f82ae0a7";
+    fsType = "ext4";
+  };
 
-  fileSystems."/boot" =
-    { device = "/dev/disk/by-uuid/0AC0-73EA";
-      fsType = "vfat";
-      options = [ "fmask=0022" "dmask=0022" ];
-    };
+  fileSystems."/boot" = {
+    device = "/dev/disk/by-uuid/0AC0-73EA";
+    fsType = "vfat";
+    options = [
+      "fmask=0022"
+      "dmask=0022"
+    ];
+  };
 
   swapDevices = [ ];
 
@@ -45,6 +61,10 @@
   services.xserver.videoDrivers = [ "nvidia" ];
 
   hardware.nvidia = {
+    # The GTX 960 GPU in this system needs a legacy driver. It isn't supported
+    # by the current 595 driver that is stable as of 2026-06-04
+    package = config.boot.kernelPackages.nvidiaPackages.legacy_580;
+
     modesetting.enable = true;
 
     # Nvidia power management. Experimental, and can cause sleep/suspend to fail.