nixos/plasma6: add CAP_SYS_NICE for kwin_wayland

This makes kwin_wayland successfully gain SCHED_RR priority, which
significantly improves the rendering lag, ie. cursor movement and
desktop animations, under heavy CPU load like on compilation.
This was already enabled for plasma5 but is not for plasma6 somehow.

1 files changed, 9 insertions, 0 deletions

diff --git a/nixos/modules/services/desktop-managers/plasma6.nix b/nixos/modules/services/desktop-managers/plasma6.nix
index 08507b4d370a7..842b0716b928d 100644
--- a/nixos/modules/services/desktop-managers/plasma6.nix
+++ b/nixos/modules/services/desktop-managers/plasma6.nix
@@ -286,6 +286,15 @@ in {
       kde-smartcard = lib.mkIf config.security.pam.p11.enable { p11Auth = true; };
     };
 
+    security.wrappers = {
+      kwin_wayland = {
+        owner = "root";
+        group = "root";
+        capabilities = "cap_sys_nice+ep";
+        source = "${lib.getBin pkgs.kdePackages.kwin}/bin/kwin_wayland";
+      };
+    };
+
     programs.dconf.enable = true;
 
     programs.firefox.nativeMessagingHosts.packages = [kdePackages.plasma-browser-integration];