Unity8 session fails to start due to unity-system-compositor

[Guillaume F]

Hi,

I've upgraded to 16.10 to try out the latest and the greatest. Unfortunately, the Unity8 session does not work anymore. It was working as expected on 16.04 with the overlay PPA.

When I select "Unity8" in lightdm and enter my password, the password box disappears, and nothing else happens. I can still access all the indicators, so lightdm is not completely frozen. I then have to reboot or restart lightdm in tty1 to log in Unity 7.

I do have a "system problem detected" warning and I did send the report, but I can't find it on Launchpad, that's why I'm filing this bug manually.

I'm using Ubuntu 16.10 64bits, with the opensource radeon driver.

Further info from the automatic bug report:
Title : unity-system-compositor crashed with SIGABRT in __gnu_cxx::__verbose_terminate_handler()

I'm attaching some logs that might be useful.

Thanks!

[Daniel van Vugt (vanvugt)]

I can't reproduce any such problem on a pure 16.10 install. The error:

  what(): option cannot be specified more than once

implies that your lightdm is passing an extra option when it executes the unity-system-compositor command.

[Guillaume F (marsguo)]

Is there any more log I can provide that could shed a light on this? This bug is very easily reproducible on my computer, so I should be able to provide relevant logs!

My computer is not a fresh install and has been upgraded every step of the way since 14.10. I'll try a LiveUSB of 16.10 to see if the problem persists.

[Robert Ancell (robert-ancell)]

The lightdm log shows the following being called:

/usr/sbin/unity-system-compositor.sleep --file '/run/mir_socket' --from-dm-fd 12 --to-dm-fd 21 --vt 8

There's no duplicate entries there...

[Robert Ancell (robert-ancell)]

If your copy of /usr/sbin/unity-system-compositor.sleep is the same as mine then the full command is:
/usr/sbin/unity-system-compositor --disable-inactivity-policy=true --on-fatal-error-abort --file '/run/mir_socket' --from-dm-fd 12 --to-dm-fd 21 --vt 8

[Daniel van Vugt (vanvugt)]

Please attach a copy of /usr/sbin/unity-system-compositor.sleep from the affected machine.

I'm surprised boost::program_options doesn't provide more information but we can investigate that separately...

[Daniel van Vugt (vanvugt)]

Note that --on-fatal-error-abort is not a valid option, and just causes a warning to be emitted.

And if you specify a valid option twice, it should tell you explicitly:

$ /usr/sbin/unity-system-compositor --vt 8 --vt 8
[2016-10-27 13:29:27.409922] mirplatform: Found graphics driver: mir:mesa-x11 (version 0.24.0)
[2016-10-27 13:29:27.411185] mirplatform: Found graphics driver: mir:mesa-kms (version 0.24.0)
Failed to parse command line options: option '--vt' cannot be specified more than once.
usage: /usr/sbin/unity-system-compositor [options]
...

Sounds like either an old out of date unity-system-compositor is installed or something else completely is throwing that exception. I can't seem to make unity-system-compositor fail in a cryptic way like yours.

[Daniel van Vugt (vanvugt)]

Most likely this is an upgrade and/or upgrade+PPA problem. Please try pure Ubuntu 16.10.

[Guillaume F (marsguo)]

Here is a copy of my unity-system-compositor.sleep.

A failed upgrade is possible: before I upgraded to 16.10, I tried purging a few PPAs because they are often problematic and purging the overlay-ppa proved very difficult (ended up chasing the word "overlay" in Synaptic to completely remove any trace).

Currently, my version of unity-system-compositor is 0.7.1+16.10.20160909.1-0ubuntu1 and Synaptic marks it as the latest version.

[Guillaume F (marsguo)]

Also, I don't know if there is an overlay-ppa for 16.10, but if there is, I did not install it on my machine, so I should be using pure 16.10 repos.