race condition between android container and powerd may disable auto brightness availability

[You-Sheng Yang]

powerd has upstart startup condition "start on started dbus and android", so it's started after android container for sure. However, android init may take some time to really bring up its property service, and powerd has to read android property "ro.product.device" when initializing its device config. On some devices, there are chances that powerd starts up before android property service is ever ready and leaving following messages in syslog:

  powerd[2506]: Initializing powerd.
  powerd[2506]: owner id: 1
  powerd[2506]: Could not determine device, running without config
  powerd[2506]: libsuspend: detect module: autosleep.
  powerd[2506]: light_dev: setting brightness to 102
  powerd[2506]: Could not determine platform autobrightness capability, disabling

[You-Sheng Yang (vicamo)]

I tried to add following poll loop to powerd upstart conf as ubuntu-location-service does, but some device still fails to retrieve correct property.

  # wait for Android properties system to be ready
  while [ ! -e /dev/socket/property_service ]; do sleep 0.1; done

Instead, the follow poll guarantees property availability.

  while [ -z "$(getprop ro.product.device)" ]; do sleep 0.1; done

[You-Sheng Yang (vicamo)]

It turns out, getprop is not a good signal to go, either. getprop and powerd all link to libandroid-properties.so.1 to retrieve Android properties. In some cases getprop succeeds but powerd still fails.

[kevin gunn (kgunn72)]

assigning to alf for repowerd consideration.
unsure if this is something worthy to be addressed in the near term

[kevin gunn (kgunn72)]

@john-mc not sure this is really a powerd thing as much as a launching sequence ?

[John McAleely (john.mcaleely)]

@w-ondra, would this get fixed with your planned 'signal when android is active'?

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Timo Jyrinki (timo-jyrinki)]

This happened on turbo with OTA-11 for me. I haven't been able to restore the automatic control now with multiple reboots, only manual control is possible.