Displaylink: Difference between revisions

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VisualWikitext

@@ Line 10: / Line 10: @@
   displaylink
 ];
-</syntaxhighlight>Then add the videoDrivers:<syntaxhighlight lang="nixos">services.xserver.videoDrivers = [ "displaylink" "modesetting" ];</syntaxhighlight>The module <code>nixos/modules/hardware/video/displaylink.nix</code> should also work for wlroots compositors.
+</syntaxhighlight>Then add the videoDrivers:<syntaxhighlight lang="nix">services.xserver.videoDrivers = [ "displaylink" "modesetting" ];</syntaxhighlight>The module <code>nixos/modules/hardware/video/displaylink.nix</code> should also work for wlroots compositors.
-====Connecting a second external monitor====
+====<big>Xserver</big>====
+=====Connecting a second external monitor=====
 In order to add a second external monitor you can add the following to your configuration:
@@ Line 18: / Line 19: @@
      ${lib.getBin pkgs.xorg.xrandr}/bin/xrandr --setprovideroutputsource 2 0
 '';</syntaxhighlight>
+[[Category:Video]]
+====Wayland====
+At first add displayLink driver to nix store as above described.
+=====evdi module=====
+You probably will need the `evdi` module
+<syntaxhighlight lang="nix">
+boot = {
+  extraModulePackages = [ config.boot.kernelPackages.evdi ];
+  initrd = {
+    # List of modules that are always loaded by the initrd.
+    kernelModules = [
+      "evdi"
+    ];
+  };
+};
+</syntaxhighlight>
+====='''Gnome Wayland'''=====
+Install displayLink package
+<syntaxhighlight lang="nix">
+environment.systemPackages = with pkgs; [
+  displaylink
+];
+</syntaxhighlight>
+Define videoDrivers
+{{bc|<nowiki>
+services.xserver.videoDrivers = [ "displaylink" ];
+</nowiki>}}
+Add dlm service
+<syntaxhighlight lang="nix">
+systemd.services.dlm.wantedBy = [ "multi-user.target" ];
+</syntaxhighlight>
+====='''KDE Plasma'''=====
+Apparently KDE Plasma (Wayland) requires a slight different approach.
+Esnure you properly enabled wayland session
+<syntaxhighlight lang="nix">
+environment.variables = {
+  KWIN_DRM_PREFER_COLOR_DEPTH = "24";
+};
+services = {
+  desktopManager.plasma6 = {
+    enable = true;
+  };
+  displayManager = {
+    sddm = {
+      enable = true;
+      wayland.enable = true;
+    };
+    defaultSession = "plasma";
+  };
+};
+</syntaxhighlight>
+Install displayLink package
+<syntaxhighlight lang="nix">
+environment.systemPackages = with pkgs; [
+  displaylink
+];
+</syntaxhighlight>
+Instead of dlm setup display-link server as follows:
+<syntaxhighlight lang="nix">
+systemd.services.displaylink-server = {
+  enable = true;
+  requires = [ "systemd-udevd.service" ];
+  after = [ "systemd-udevd.service" ];
+  wantedBy = [ "multi-user.target" ];
+  serviceConfig = {
+    Type = "simple";
+    ExecStart = "${pkgs.displaylink}/bin/DisplayLinkManager";
+    User = "root";
+    Group = "root";
+    Restart = "on-failure";
+    RestartSec = 5; # Wait 5 seconds before restarting
+  };
+};
+</syntaxhighlight>
 ==Sway==
@@ Line 53: / Line 147: @@
 [https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/1823#note_2146862 Source]
+== Troubleshooting ==
+=== Suspend blocked by <code>pre-sleep.service</code> ===
+As of NixOS 25.05, installing <code>pkgs.displaylink</code> inserts some directives into the script referenced by <code>pre-sleep.service</code>. If suspending does not work and causes the reboot and poweroff buttons to stop working, it may be a symptom of [[Power Management#Suspend blocked by pre-sleep.service|suspend being blocked by pre-sleep.service]].
+The script in question:<syntaxhighlight lang="bash" line="1">
+#!/nix/store/cfqbabpc7xwg8akbcchqbq3cai6qq2vs-bash-5.2p37/bin/bash
+set -e
+#flush any bytes in pipe
+while read -n 1 -t 1 SUSPEND_RESULT < /tmp/PmMessagesPort_out; do : ; done;
+#suspend DisplayLinkManager
+echo "S" > /tmp/PmMessagesPort_in
+#wait until suspend of DisplayLinkManager finish
+if [ -f /tmp/PmMessagesPort_out ]; then
+  #wait until suspend of DisplayLinkManager finish
+  read -n 1 -t 10 SUSPEND_RESULT < /tmp/PmMessagesPort_out
+fi
+</syntaxhighlight>Because of a stray <code>/tmp/PmMessagesPort_out</code> caused by an unclean shutdown, the suspend action was blocked by this script trying to flush the port. A myriad of solutions can be used to unblock the script and restore suspend:
+* Start <code>dlm.service</code> so that DisplayLinkManager can clear the ports and unblock the script
+* Use <code>sudo DisplayLinkManager</code> to clear the ports and unblock the script
+Untested solutions:
+* Removing the file
+* Killing the script
 [[Category:Video]]