diff --git a/dix/inpututils.c b/dix/inpututils.c
index eb2222a07..9e38e1742 100644
--- a/dix/inpututils.c
+++ b/dix/inpututils.c
@@ -1015,6 +1015,21 @@ xi2mask_free(XI2Mask **mask)
     *mask = NULL;
 }
 
+/**
+ * Test if the bit for event type is set for this device only.
+ *
+ * @return TRUE if the bit is set, FALSE otherwise
+ */
+Bool
+xi2mask_isset_for_device(XI2Mask *mask, const DeviceIntPtr dev, int event_type)
+{
+    BUG_WARN(dev->id < 0);
+    BUG_WARN(dev->id >= mask->nmasks);
+    BUG_WARN(bits_to_bytes(event_type + 1) > mask->mask_size);
+
+    return BitIsOn(mask->masks[dev->id], event_type);
+}
+
 /**
  * Test if the bit for event type is set for this device, or the
  * XIAllDevices/XIAllMasterDevices (if applicable) is set.
@@ -1026,15 +1041,12 @@ xi2mask_isset(XI2Mask *mask, const DeviceIntPtr dev, int event_type)
 {
     int set = 0;
 
-    BUG_WARN(dev->id < 0);
-    BUG_WARN(dev->id >= mask->nmasks);
-    BUG_WARN(bits_to_bytes(event_type + 1) > mask->mask_size);
-
-    set = ! !BitIsOn(mask->masks[XIAllDevices], event_type);
-    if (!set)
-        set = ! !BitIsOn(mask->masks[dev->id], event_type);
-    if (!set && IsMaster(dev))
-        set = ! !BitIsOn(mask->masks[XIAllMasterDevices], event_type);
+    if (xi2mask_isset_for_device(mask, inputInfo.all_devices, event_type))
+        set = 1;
+    else if (xi2mask_isset_for_device(mask, dev, event_type))
+        set = 1;
+    else if (IsMaster(dev) && xi2mask_isset_for_device(mask, inputInfo.all_master_devices, event_type))
+        set = 1;
 
     return set;
 }
diff --git a/include/inpututils.h b/include/inpututils.h
index cd9a4de82..53c96ba1c 100644
--- a/include/inpututils.h
+++ b/include/inpututils.h
@@ -57,6 +57,7 @@ XI2Mask *xi2mask_new(void);
 XI2Mask *xi2mask_new_with_size(size_t, size_t); /* don't use it */
 void xi2mask_free(XI2Mask **mask);
 Bool xi2mask_isset(XI2Mask *mask, const DeviceIntPtr dev, int event_type);
+Bool xi2mask_isset_for_device(XI2Mask *mask, const DeviceIntPtr dev, int event_type);
 void xi2mask_set(XI2Mask *mask, int deviceid, int event_type);
 void xi2mask_zero(XI2Mask *mask, int deviceid);
 void xi2mask_merge(XI2Mask *dest, const XI2Mask *source);
diff --git a/test/xi2/xi2.c b/test/xi2/xi2.c
index 6ee705293..1cdad1dbd 100644
--- a/test/xi2/xi2.c
+++ b/test/xi2/xi2.c
@@ -36,8 +36,14 @@ xi2mask_test(void)
     XI2Mask *xi2mask = NULL, *mergemask = NULL;
     unsigned char *mask;
     DeviceIntRec dev;
+    DeviceIntRec all_devices, all_master_devices;
     int i;
 
+    all_devices.id = XIAllDevices;
+    inputInfo.all_devices = &all_devices;
+    all_master_devices.id = XIAllMasterDevices;
+    inputInfo.all_master_devices = &all_master_devices;
+
     /* size >= nmasks * 2 for the test cases below */
     xi2mask = xi2mask_new_with_size(MAXDEVICES + 2, (MAXDEVICES + 2) * 2);
     assert(xi2mask);