Can cause device to lock up by stressing greeter and lock screen.

[Thomi Richards]

By swiping away the greeter and pressing the lock screen button (power button) I can cause the Nexus 4 (mako) to get into a state where:

 * The screen is blank (with no backlight).
 * The screen does not repsond to touch events.
 * I cannot get the greeter screen back by pushing the power button.
 * I cannot reboot the device with 'adb reboot'.
 * The only way to get the device working again is to hold the power button down and force a restart.

Reproducing isn't too hard:

from the greeter screen, swipe the screen away, and then quickly press the power button several times in quick succession. You need to be quick, but I can reproduce this pretty reliably.

[Thomi Richards (thomir-deactivatedaccount)]

Upon further investigation, you don't even need to use the lock screen. If you're fast enough, you can get it to lock up without any swiping. My favorite method is to rest the power button on the corner of the desk, which makes it easier to tap the button fast enough.

[Nicholas Skaggs (nskaggs)]

confirmed, thomi it would be best to use omer's tool and attach some logs from the event.

[Thomi Richards (thomir-deactivatedaccount)]

balloons: I'm not sure what tool you're referring to: apport-cli? That won't help here since there's no crash. On top of that, you can't do anything with the phone except reboot it, so I'm not sure what else I can do...

[wojox (wojox)]

I caught a log. At about line #76 I started pressing the power button. http://paste.ubuntu.com/6143165/

[wojox (wojox)]

I was able to reproduce on nexus7.

[Thomi Richards (thomir-deactivatedaccount)]

Still happens on a mako, build 13 (trusty channel).

[Kevin DuBois (kdub)]

might be https://bugs.launchpad.net/powerd/+bug/1258655