diff --git a/sysutils/plasma5-powerdevil/files/patch-daemon_backends_upower_freebsdbacklighthelper.cpp b/sysutils/plasma5-powerdevil/files/patch-daemon_backends_upower_freebsdbacklighthelper.cpp
new file mode 100644
index 000000000000..6e79ebfdd181
--- /dev/null
+++ b/sysutils/plasma5-powerdevil/files/patch-daemon_backends_upower_freebsdbacklighthelper.cpp
@@ -0,0 +1,17 @@
+Fix build on FreeBSD 12.x.
+
+/usr/include/sys/sysctl.h:1117:25: error: unknown type name 'u_int'; did you mean 'uint'?
+int     sysctl(const int *, u_int, void *, size_t *, const void *, size_t);
+                            ^
+--- daemon/backends/upower/freebsdbacklighthelper.cpp.orig	2023-12-11 05:59:31 UTC
++++ daemon/backends/upower/freebsdbacklighthelper.cpp
+@@ -31,8 +31,8 @@
+ 
+ #include <algorithm>
+ #include <climits>
+-#include <sys/sysctl.h>
+ #include <sys/types.h>
++#include <sys/sysctl.h>
+ #include <sys/utsname.h>
+ 
+ #define BACKLIGHT_PATH "/dev/backlight/"