Sometimes at first bootup, I'm seeing the HomeScreen service start after the WindowManager service, which means HomeScreen exits with this error:

Failed to create display (No such file or directory)

Note that it seems like I can repro this only on first boot, suggesting a possible interaction with the agl-postinsts scripts.

From my reading of the HomeScreen systemd service file, this should not be possible:

Requires=dbus.service afm-user-daemon.service InputEventManager.service HomeScreenAppFrameworkBinderAGL.service
After=dbus.service afm-user-daemon.service InputEventManager.service HomeScreenAppFrameworkBinderAGL.service WindowManager.service

Note that After= contains WindowManager.service, as it should.

I've attached /var/log/messages for a case in which this occurred. Strangely, the log entries seem to be out of order (many entries logged as 23:21:20, which can't be possible), so be careful when looking at the logs.

line 368:

May  3 23:21:20 qemux86-64 daemon.info systemd[658]: Started AGL Window Manager.

line 582:

May  3 23:21:20 qemux86-64 daemon.info HomeScreen[739]: Failed to create display (No such file or directory)

line 605:

May  3 23:21:20 qemux86-64 daemon.info systemd[658]: Starting AGL Window Manager...