Allow triggering an alarm while device is off

[tibbi]

A new permission Power Off Alarm or so might be needed

[liyamahendra]

@tibbi In Android, it is not possible to trigger an alarm while the device is completely powered off. When the device is powered off, all processes and applications, including alarms, are not active.

However, if the device is in a sleep mode or standby mode, you can schedule an alarm to wake up the device and trigger an action.

Let me know your thoughts on this or if I misunderstood the feature request.

[liyamahendra]

Just to add, RTC_WAKEUP flag cannot wake up a device that is completely turned off. The RTC_WAKEUP flag is only effective when the device is in sleep mode or idle state, such as when the screen is turned off or the device is in a low-power state.

[tibbi]

note for future reference: Some relevant LineageOS commits for implementing this are at LineageOS/android_packages_apps_DeskClock@af3a2d2 and LineageOS/android_packages_apps_DeskClock@cbde2cd