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[Bug 1552371] Re: Unexpected display on

 

> So you are saying we should have the proximity sensor on all the time ?
> I disagree, first that's a power drain. Second, people will complain about the screen blanking off just interacting with the device.

There is a third, ideal way which would be to check the proximity value
just before making the transition from off to on. This is currently
difficult due to the overall power management architecture and the fact
that the proximity API given to us doesn't provide a query function (we
get change events, but can't get the current state). In the current
system we have worked around this for SMS, calls etc with some funky
hacks in USC and powerd which would be difficult to extend to other use
cases. In the new architecture I expect that we will be able to manage
proximity (and this case in particular) much more elegantly.

> The right answer is to get the policy correct in the first place and
filter the events properly into those that you want to turn on the
display and those you don't.

This is correct. Currently USC wakes up the screen when any key other
than power and volume (which are handled specially) or a pointer events
arrive. Perhaps there is a bug in our input subsystem and we send stray
key events, or perhaps the events are valid (some kind of special key
event not corresponding to user input?) and we should filter more
strictly. In any case, we need to find out more about these unexpected
events to make an informed decision.

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https://bugs.launchpad.net/bugs/1552371

Title:
  Unexpected display on

Status in Canonical System Image:
  Confirmed
Status in bluez package in Ubuntu:
  New
Status in unity-system-compositor package in Ubuntu:
  New

Bug description:
  NOTE: kgunn suggests this bug be about 1) not 2) here

  1)
  I have been noticing my phone and tablet occasionally turning on without interaction. Several times with my phone in my pocket I found it in the emergency call UI
  I also see the tablet display turn on while lying idle on the desk.

  2)
  I have reproduced one case such that turning on a BT device (headset) causes the phone to light up and display the volume slider. Similarly turning on the BT keyboard while the tablet screen is off caused the display to turn on.These may be as intended.

  I suspect other BT events can similarly resume the device and/or turn on the display if it happens to be awake due to the 5 min polling timer.
  The proximity sensor is also not honored when this happens, if its covered the screen still comes on.

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