DeviceState: Use AlarmManager for time schedule#84
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chenxiaolong merged 1 commit intomasterfrom Apr 7, 2026
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Previously, the timers were based on the SystemClock.uptimeMillis() clock, which is monotonic, but pauses while the device is in deep sleep. For devices that enter deep sleep frequently, a time interval based on this clock can be significantly longer than the same interval based on wall time. This commit changes the timer mechanism to use AlarmManager instead. There are a couple caveats here: * AlarmManager enforces that the execution time is at least 5 seconds into the future in AOSP, but Google and OEMs can override this at runtime via DeviceConfig. This is unlikely to matter much since users are generally going to be configuring intervals in the minutes or hours. * The intervals are no longer exact, even when the device is awake. AlarmManager.set() always tries to batch calls to avoid unnecessary wakeups. AlarmManager.setExact() is intentionally not used in this initial implementation. This can be revisited in the future if devices are scheduling wakeups too much later than what the user expects. Fixes: #83 Signed-off-by: Andrew Gunnerson <accounts+github@chiller3.com>
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Signed-off-by: Andrew Gunnerson <accounts+github@chiller3.com>
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Previously, the timers were based on the
SystemClock.uptimeMillis()clock, which is monotonic, but pauses while the device is in deep sleep. For devices that enter deep sleep frequently, a time interval based on this clock can be significantly longer than the same interval based on wall time.This commit changes the timer mechanism to use
AlarmManagerinstead. There are a couple caveats here:AlarmManagerenforces that the execution time is at least 5 seconds into the future in AOSP, but Google and OEMs can override this at runtime viaDeviceConfig. This is unlikely to matter much since users are generally going to be configuring intervals in the minutes or hours.The intervals are no longer exact, even when the device is awake.
AlarmManager.set()always tries to batch calls to avoid unnecessary wakeups.AlarmManager.setExact()is intentionally not used in this initial implementation. This can be revisited in the future if devices are scheduling wakeups too much later than what the user expects.Fixes: #83