Lenovo Legion 16achg6: Fix gpu configuration to work with both x11/wa…

…yland (#802)

Co-authored-by: Alojzy Leszcz <[email protected]>

lenovo/legion/16achg6/README.md

@@ -1,4 +1,6 @@
-I personally use my laptop with an external display attached. In `hybrid` config it works nice only with Wayland, while X11 can't detect the external monitor. Everything works as expected in `nvidia` mode, but battery life is reduced then.
+I personally use my laptop with an external display attached and haven't observed any issues so far.
+
+From my experience, it's better to use gdm, as sddm seems to have a problem detecting the external monitor (more details available [here](https://github.com/sddm/sddm/issues/1558)). Of course it's not a blocker, as it is still possible to log in using sddm. I personally find it annoying that my main display remains idle.
 
 ## Setup at the time of testing
 ```

lenovo/legion/16achg6/hybrid/default.nix

@@ -10,12 +10,14 @@
     ../../../../common/pc/laptop/ssd
   ];
 
-  services.xserver.videoDrivers = [ "nvidia" "amdgpu" ];
+  services.xserver.videoDrivers = [ "nvidia" ];
+  boot.initrd.kernelModules = [ "amdgpu" ];
 
   hardware = {
     nvidia = {
       modesetting.enable = lib.mkDefault true;
       powerManagement.enable = lib.mkDefault true;
+      open = lib.mkDefault false;
 
       prime = {
         amdgpuBusId = "PCI:5:0:0";