Sometimes devices don't suspend - display turns back on immediately

adding u-s-c as I'm not sure unity8 will even be involved here

Is there an app running (perhaps in the background) that's keeping the screen on?

setting to incomplete. It didn't happen on recent builds.

It happened again this morning on arale rc-proposed 260.

The only apps started after last reboot nearly 3 hours ago are dekko and the calculator.

Actually what happens today is I press the power button to suspend the device, and the screen immediately turns back on.

list of running processes.

No app is running (at least nothing visible in the spread)

I entered bug #1552371 which could be related especially given the report that a key event had occurred at the time.

With the help of Jean-Baptiste I was able to get some more information from a device exhibiting the problem.

The logs indicate that the phone is continuously receiving repeat key events (scancode=125=left-meta) from the touchscreen input device. These events are keeping the device awake.

This seems to be another instance of bug 1550050, which involves the Mir input subsystem sending key repeat events event after an input device disappears. In this case the repeated key is the circular touch key at the bottom of the MX4 (which is sent as left-meta). A fix for this is included in the upcoming Mir 0.20.2 release.

I have added steps to reproduce this on MX4 in the description.

The only difference to the mentioned lp:#1550050 is that the device is not "removed" during suspend, which I suspect was fixed in lp:mir and will be included in 0.21.0 - this together with the fix for #1550050 should solve that problem.

We need a different solution here since we never stop reading from the the touchscreen when the screen is off. Instead the hardware is turned off so it never sends a release..

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

This bug was fixed in the package mir - 0.21.0+16.04.20160330-0ubuntu1

---------------
mir (0.21.0+16.04.20160330-0ubuntu1) xenial; urgency=medium

  [ Alberto Aguirre ]
  * New upstream release 0.21.0 (https://launchpad.net/mir/+milestone/0.21.0)
    - ABI summary:
      . mirclient ABI unchanged at 9
      . mirserver ABI unchanged at 38
      . mircommon ABI unchanged at 5
      . mirplatform ABI unchanged at 11
      . mirprotobuf ABI unchanged at 3
      . mirplatformgraphics ABI unchaged at 8
      . mirclientplatform ABI bumped to 5
      . mirinputplatform ABI unchanged at 5
    - Enhancements:
      . New display enumeration API
      . Added Android diagnostic tests to assist during porting to
        new devices
      . Added mir_demo_client_camera: a Video4Linux2 client
    - Bugs fixed:
      . Sometimes devices don't suspend - display turns back on
        immediately (LP: #1549701)
      . Mir crashed with exception 'failed to add sync point to command
        buffer' (LP: #1554635)
      . Mouse cursor is unusably slow in Unity 8 with a 1000Hz mouse
        (LP: #1539009)
      . Packaged mir_unit_tests binary is not suitable for general use
        (LP: #1547015)
      . [regression] Mir stops receiving input after a pause/resume
        cycle (LP: #1548989)
      . NBS (--nbuffers=0) causes software clients to crash with
        std::exception::what: Failed to mmap buffer 13, "Permission denied")
        (LP: #1550432)
      . Fullscreen clients freeze when using NBS with multiple monitors
        (LP: #1551536)
      . [ FAILED ] DisplayConfigurationTest.output_position_is_independent_of_
        orientation (LP: #1552065)
      . The server-side use of MIR_SOCKET is confusing (LP: #1290345)
      . [regression] FTBFS with -DMIR_LINK_TIME_OPTIMIZATION=on
        -Duse_debflags=on (LP: #1350343)
      . Mir On X (mesa-x11) keeps receiving mouse movement events even
        when not focused (LP: #1528110)
      . x11 platform: mouse cursor moves strange (LP: #1546324)
      . Cross compiling to wily/vivid doesn't work (LP: #1549152)
      . Rendering stutters when a new client establishes a connection
        (LP: #1549359)
      . 'mir_demo_server --test-client' crashes (SIGSEGV) when client
        dies (LP: #1555620)
      . [testfail] CI failure: TestClientInput.client_input_config_request_
        receives_all_attached_devices (LP: #1555708)
      . [regression] Mir FTBFS when MIR_ENABLE_TESTS=no (LP: #1556080)
      . Mir-on-X11 doesn't exit (until it gets an event) (LP: #1556210)
      . InputPlatformProbe.x11_platform_found_and_used_when_display_connection_
        works breaks with old input drivers present (LP: #1543049)
      . [regression] MIR_CLIENT_PERF_REPORT is missing window/surface
        names (LP: #1546933)
      . Installed binaries fail to run with mir_demo_server --test-client XXXX
        (LP: #1556160)
      . mir_demo_server --test-client [mir_demo_client_scroll|
        mir_demo_client_flicker] fails (LP: #1556205)
      . The contents of debian/mir-demos.examples are out of date and useless
        (LP: #1557446)

  [ CI Train Bot ]
  * No-change rebuild.

 -- Alberto Aguirre <alberto.aguirre@can...

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 0.22.0