[Regression] [Trusty] Unity can't be started from kdm

[Albert Astals Cid]

Because of https://launchpadlibrarian.net/169426095/gnome-session_3.9.90-0ubuntu11_3.9.90-0ubuntu12.diff.gz i can't log in into an Unity session from kdm

[Sebastien Bacher (seb128)]

Thanks, the issue is due to the DESKTOP_SESSION -> XDG_CURRENT_DESKTOP change. kdm exports the first variable but not the second one, it makes the upstart job bail out on "Unknown parameter: XDG_CURRENT_DESKTOP"

We either need to revert to use DESKTOP_SESSION back or to fix kdm (and potential other dms) to set XDG_CURRENT_DESKTOP

Dimitri, Dmitry, Tim, you are the ones that worked on those changes, is any of you wanting to look at changing kdm or should we just revert that update?

[Dmitry Shachnev (mitya57)]

I would prefer to fix KDM or wait for Tim to propose an alternative to his changes.

[Sebastien Bacher (seb128)]

Right, fixing KDM would be nice, the issue is to know if anyone has spare cycles to work on that...

[Albert Astals Cid (aacid)]

Is there anything in a spec somewhere that says kdm is at wrong here and that it should indeed define XDG_CURRENT_DESKTOP ?

[Sebastien Bacher (seb128)]

No, XDG_CURRENT_DESKTOP is an Ubuntu specific thing at the moment, we have been talking about it standardized on freedesktop though (it should be discussed at the next fdo summit)

[Tim Lunn (darkxst)]

XDG_CURRENT_DESKTOP needs to be set by the DM, otherwise GNOME and probably Unity sessions will be buggy.

[Albert Astals Cid (aacid)]

It works fine here without the DM setting it. Note that the variable is set, probably by something else.

[Sebastien Bacher (seb128)]

gnome-session is setting it so the session itself is fine, the issue is that the gnome-session upstart job is not benefiting from that

[Tim Lunn (darkxst)]

@Albert, any job run as an upstart user session, will not have access to that variable, at the very least that affects the gnome-session job and also gnome-settings-daemon

[Albert Astals Cid (aacid)]

Ok, feel free to mark this as invalid if you don't care that Unity fails to start from other DM than lightdm.

[Becache (msn-adam)]

Is there any updates or how can I start gnome session from kdm ?

[Rik Mills (rikmills)]

Still present in utopic.

[Rik Shaw (rik-shaw)]

I haven't found out how to set XDG_CURRENT_DESKTOP from mdm (Linux Mint's fork of older gdm), so then when attempting to login to Gnome-Shell I am greeted with a black screen. However, doing this is a workaround (but still leaves XDG_CURRENT_DESTKOP unset):

in /usr/share/upstart/sessions/gnome-session.conf

change:

instance $XDG_CURRENT_DESKTOP

to:

instance GNOME

[Albert Astals Cid (aacid)]

This doesn't seem like it's getting any traction after 2 years and kdm is not even shipped anymore so as reporter i'm closing this bug to have a cleaner "reported bugs" view in launchpad.

[Timo Jyrinki (timo-jyrinki)]

It affects sddm too.

[Tim Lunn (darkxst)]

sddm should grow support to set XDG_CURRENT_DESKTOP

XDG_CURRENT_DESKTOP was standardised a while back.