examples: fix the uinput example so it actually does what users expect

The previous one was technically correct, but a device with just EV_REL won't
get tagged by udev as mouse and won't get picked up by anything proper. And
likewise, without a delay before sending the event, the events won't get
picked up by userspace. Change that, so the example moves the pointer a bit
which is what a user would expect.

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

examples/uinput.py

@@ -3,6 +3,7 @@
 import sys
 import libevdev
 from libevdev import InputEvent
+import time
 
 
 def main(args):
@@ -10,14 +11,24 @@ def main(args):
     dev.name = "test device"
     dev.enable(libevdev.EV_REL.REL_X)
     dev.enable(libevdev.EV_REL.REL_Y)
+    dev.enable(libevdev.EV_KEY.BTN_LEFT)
+    dev.enable(libevdev.EV_KEY.BTN_RIGHT)
     try:
         uinput = dev.create_uinput_device()
         print("New device at {} ({})".format(uinput.devnode, uinput.syspath))
 
-        events = [InputEvent(libevdev.EV_REL.REL_X, -1),
-                  InputEvent(libevdev.EV_REL.REL_Y, 1),
-                  InputEvent(libevdev.EV_SYN.SYN_REPORT, 0)]
-        uinput.send_events(events)
+        # Sleep for a bit so udev, libinput, Xorg, Wayland, ... all have had
+        # a chance to see the device and initialize it. Otherwise the event
+        # will be sent by the kernel but nothing is ready to listen to the
+        # device yet.
+        time.sleep(1)
+
+        for _ in range(5):
+            events = [InputEvent(libevdev.EV_REL.REL_X, -1),
+                      InputEvent(libevdev.EV_REL.REL_Y, 1),
+                      InputEvent(libevdev.EV_SYN.SYN_REPORT, 0)]
+            time.sleep(0.012)
+            uinput.send_events(events)
     except OSError as e:
         print(e)