we recently starting deploying our device to a number of test customers. Our device shall sleep (suspend to ram) most of the time, but it can be woken up by SMS and a couple of GPIOs.
While browsing through the logfiles from our test devices, we saw a couple of wakeups which we couldn’t explain. Some colleagues are already starting to blame EMF radiation.
So I was wondering if there is a way to track down the reason for each single wakeup:
Can Legato notify our application after a wakeup occured?
Can we query the wakeup reason from Legato or from the kernel then? (I noticed /sys/kernel/wakeup_reasons/last_resume_reason, but it seems to be always empty)
Is there any kernel debug output we could activate to log the wakeup reason?
we observed that these wakeups are happening more frequent at places with no/or bad network signal (e.g. underground parking).
the wakeups are not happening anymore if we switch on airplane mode (cm radio off)
=> so our conclusion right now is that these wakeups are caused by the baseband processor.
We are just wondering: is that an intended - to be expected - behavior? Does the baseband processor actively wakeup the application processor regularly in case network signal is bad?
Or are we suffering from some kind of electrical side-effect?