System state goes to off while display state does not

[Alfonso Sanchez-Beato]

I start a voice call. I cover the proximity sensor (screen goes black), then uncover it (screen comes back). Then I finish the call. The events generated by powerd are:

# powerd-cli listen
Waiting for events, press ctrl-c to quit
Received DisplayPowerStateChange: state=1 flags=0x000005
Received SysPowerStateChange: state=0 --> Sensor covered
Received SysPowerStateChange: state=1 --> Sensor uncovered
Received DisplayPowerStateChange: state=1 flags=0x000004

As can be seen from the traces, the system state goes to off whilst the display state is always on. This should not happen as the display state in powerd is supposed to take a system request while the display is on to prevent system suspend.