diff --git a/src/libei-device.c b/src/libei-device.c
index 11a399b..fb4c525 100644
--- a/src/libei-device.c
+++ b/src/libei-device.c
@@ -33,6 +33,30 @@
 
 #include "libei-private.h"
 
+static const char *
+ei_device_state_to_string(enum ei_device_state state)
+{
+	switch (state) {
+	CASE_RETURN_STRING(EI_DEVICE_STATE_NEW);
+	CASE_RETURN_STRING(EI_DEVICE_STATE_CONNECTING);
+	CASE_RETURN_STRING(EI_DEVICE_STATE_SUSPENDED);
+	CASE_RETURN_STRING(EI_DEVICE_STATE_RESUMED);
+	CASE_RETURN_STRING(EI_DEVICE_STATE_REMOVED);
+	}
+	assert(!"Unhandled device state");
+}
+
+static void
+ei_device_set_state(struct ei_device *device,
+		    enum ei_device_state state)
+{
+	enum ei_device_state old_state = device->state;
+	device->state = state;
+	log_debug(ei_device_get_context(device), "device %d: %s → %s\n",
+		  device->id, ei_device_state_to_string(old_state),
+		  ei_device_state_to_string(state));
+}
+
 static void
 ei_device_destroy(struct ei_device *device)
 {
@@ -188,7 +212,7 @@ _public_ void
 ei_device_add(struct ei_device *device)
 {
 	ei_add_device(device);
-	device->state = EI_DEVICE_STATE_CONNECTING;
+	ei_device_set_state(device, EI_DEVICE_STATE_CONNECTING);
 }
 
 _public_ void
@@ -197,20 +221,20 @@ ei_device_remove(struct ei_device *device)
 	if (device->state == EI_DEVICE_STATE_REMOVED)
 		return;
 
-	device->state = EI_DEVICE_STATE_REMOVED;
+	ei_device_set_state(device, EI_DEVICE_STATE_REMOVED);
 	ei_remove_device(device);
 }
 
 void
 ei_device_resumed(struct ei_device *device)
 {
-	device->state = EI_DEVICE_STATE_RESUMED;
+	ei_device_set_state(device, EI_DEVICE_STATE_RESUMED);
 }
 
 void
 ei_device_suspended(struct ei_device *device)
 {
-	device->state = EI_DEVICE_STATE_SUSPENDED;
+	ei_device_set_state(device, EI_DEVICE_STATE_SUSPENDED);
 }
 
 void