Hello
currently I am using the wp76xx + legato API to enable USBSS -
LE_ASSERT_OK(le_pm_Relax(r));
device goes to suspend
then I initiate a call, device wakes - up as expected
but, when finishing the call the device does not go back to sleep, how can I go back to sleep ?
Can you check /sys/power/wake_lock ?
that was the first thing I did 
the file behaves as expected, meaning empty when clearing the wakelock via API and have a value when “taking” the wake-lock
how ever the system does not enter and exit suspend to RAM as expected
I don’t see problem on WP76 Fw12.
During sleep mode (i.e. remove the USB cable), if I dial a phone call to the module, I can see the RING message.
Later if I drop the voice call, it goes to sleep mode automatically.
Could you list the active wakeup sources that are preventing the system to go to sleep:
awk '{print $6 "\t" $1}' /sys/kernel/debug/wakeup_sources | grep -v "^0"
I have found the reason
I had a background application that has used data connection to send data via MQTT
when I do not stop it I get:
awk ‘{print $6 “\t” $1}’ /sys/kernel/debug/wakeup_sources
| grep -v “^0”
active_since name
92803 UNIX
92483 UNIX
18 36
and system fails to go into USB-SS mode
if I stop it I get:
awk ‘{print $6 “\t” $1}’ /sys/kernel/debug/wakeup_sources
| grep -v “^0”
active_since name
12 20
and device enters USB SS mode