On my machine with Bluez 5.72 I have replaced my old BT dongle with a:
Bus 003 Device 029: ID 0bda:8771 Realtek Semiconductor Corp. [unknown]
I have a:
Name: Bluetooth Mouse M557
Alias: Bluetooth Mouse M557
Class: 0x00000580 (1408)
Icon: input-mouse
Paired: yes
Bonded: yes
Trusted: yes
Blocked: no
Connected: yes
WakeAllowed: yes
LegacyPairing: no
UUID: Service Discovery Serve.. (00001000-0000-1000-8000-00805f9b34fb)
UUID: Human Interface Device... (00001124-0000-1000-8000-00805f9b34fb)
UUID: PnP Information (00001200-0000-1000-8000-00805f9b34fb)
Modalias: usb:v046DpB010d1001
paired to it.
If I leave the computer briefly (minutes, perhaps even a small number
of hours) and return the mouse continues to work correctly.
If I leave the computer for a longer period of time, like say, over
night until the next day, when I try to use the mouse it does not work
immediately. I can take a few tens of minutes for it to "wake up" and
be functional again.
I didn't have this problem with my old BT dongle.
Any ideas how to resolve this?