USB suspended Idle mode not working in WP series

Hi Vitaly,
Can you please advise which apps could be stopped and which are necessary to keep running (if any)?
Fresh installation of 9.1 looks this way:

root@swi-mdm9x28-wp:~# app status
[running] atAirVantage
[running] atQmiLinker
[running] atService
[running] audioService
[running] avcService
[running] cellNetService
[running] dataConnectionService
[running] fwupdateService
[running] gpioService
[running] modemService
[running] portService
[running] positioningService
[running] powerMgr
[running] qmiAirVantage
[running] secStore
[stopped] smsInboxService
[stopped] spiService
[stopped] tools
[stopped] voiceCallService
[stopped] wifi
[stopped] wifiApTest
[stopped] wifiClientTest
[running] wifiService
[stopped] wifiWebAp

Is there more detail description of pre-installed apps available?

Thanks a lot.
Best regards