diff --git a/include/libcamera/internal/ipc_unixsocket.h b/include/libcamera/internal/ipc_unixsocket.h
index 9dcaaa26..e871b650 100644
--- a/include/libcamera/internal/ipc_unixsocket.h
+++ b/include/libcamera/internal/ipc_unixsocket.h
@@ -12,10 +12,12 @@
 #include <sys/types.h>
 #include <vector>
 
-#include <libcamera/event_notifier.h>
+#include <libcamera/signal.h>
 
 namespace libcamera {
 
+class EventNotifier;
+
 class IPCUnixSocket
 {
 public:
diff --git a/include/libcamera/internal/process.h b/include/libcamera/internal/process.h
index 36595106..2688557c 100644
--- a/include/libcamera/internal/process.h
+++ b/include/libcamera/internal/process.h
@@ -10,7 +10,7 @@
 #include <string>
 #include <vector>
 
-#include <libcamera/event_notifier.h>
+#include <libcamera/signal.h>
 
 namespace libcamera {
 
diff --git a/src/libcamera/ipc_unixsocket.cpp b/src/libcamera/ipc_unixsocket.cpp
index 701b2c51..5c8cce16 100644
--- a/src/libcamera/ipc_unixsocket.cpp
+++ b/src/libcamera/ipc_unixsocket.cpp
@@ -12,6 +12,8 @@
 #include <sys/socket.h>
 #include <unistd.h>
 
+#include <libcamera/event_notifier.h>
+
 #include "libcamera/internal/log.h"
 
 /**