dix: introduce GetMaster()

For hybrid devices (keys + buttons/axes) the attached master device is
generally the wrong one. One shouldn't post a button event through a
keyboard and vice versa.

GetMaster(dev) returns the right master device for the given type needed.
This may be the MD paired with this device's MD.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

dix/devices.c

@@ -2345,6 +2345,41 @@ GetPairedDevice(DeviceIntPtr dev)
 }
 
 
+/**
+ * Returns the right master for the type of event needed. If the event is a
+ * keyboard event.
+ * This function may be called with a master device as argument. If so, the
+ * returned master is either the device itself or the paired master device.
+ * If dev is a floating slave device, NULL is returned.
+ *
+ * @type ::MASTER_KEYBOARD or ::MASTER_POINTER
+ */
+DeviceIntPtr
+GetMaster(DeviceIntPtr dev, int which)
+{
+    DeviceIntPtr master;
+
+    if (IsMaster(dev))
+        master = dev;
+    else
+        master = dev->u.master;
+
+    if (master)
+    {
+        if (which == MASTER_KEYBOARD)
+        {
+            if (master->type != MASTER_KEYBOARD)
+                master = GetPairedDevice(master);
+        } else
+        {
+            if (master->type != MASTER_POINTER)
+                master = GetPairedDevice(master);
+        }
+    }
+
+    return master;
+}
+
 /**
  * Create a new device pair (== one pointer, one keyboard device).
  * Only allocates the devices, you will need to call ActivateDevice() and

dix/getevents.c

@@ -612,7 +612,10 @@ clipValuators(DeviceIntPtr pDev, int first_valuator, int num_valuators,
 static EventListPtr
 updateFromMaster(EventListPtr events, DeviceIntPtr dev, int *num_events)
 {
-    DeviceIntPtr master = dev->u.master;
+    DeviceIntPtr master;
+
+    master = GetMaster(dev, (type & DEVCHANGE_POINTER_EVENT) ?  MASTER_POINTER : MASTER_KEYBOARD);
+
     if (master && master->last.slave != dev)
     {
         CreateClassesChangedEvent(events, master, dev);
@@ -793,8 +796,10 @@ updateHistory(DeviceIntPtr dev, int first, int num, CARD32 ms)
 {
     updateMotionHistory(dev, ms, first, num, &dev->last.valuators[first]);
     if (dev->u.master)
-        updateMotionHistory(dev->u.master, ms, first, num,
-                            &dev->last.valuators[first]);
+    {
+        DeviceIntPtr master = GetMaster(dev, MASTER_POINTER);
+        updateMotionHistory(master, ms, first, num, &dev->last.valuators[first]);
+    }
 }
 
 /**

include/input.h

@@ -472,6 +472,7 @@ extern int AttachDevice(ClientPtr client,
                         DeviceIntPtr master);
 
 extern _X_EXPORT DeviceIntPtr GetPairedDevice(DeviceIntPtr kbd);
+extern DeviceIntPtr GetMaster(DeviceIntPtr dev, int type);
 
 extern int AllocDevicePair(ClientPtr client,
                              char* name,