consistent-login-screen aka UnifiedLoginUnlock

Ian Jackson iwj at ubuntu.com
Thu Jul 26 17:35:45 BST 2007


Our plan in gutsy for fixing the (un)useability of fast user switching
was described here: https://wiki.ubuntu.com/UnifiedLoginUnlock.

In summary, we were going to change gdm to not be so confusing, with
consequential changes to the screensaver and various other bits.  This
work is at a very early testing stage.

However, it now[1] looks like upstream are going in different
directions.  Relevantly:

There is a package `consolekit' which attempts to solve this problem
and a couple of related ones (eg, control over networking policy and
media mounting); it's dbus based.  Changes have already been made
upstream in gdm2 to support this.

Additionally, gdm upstream are working on a substantial overhaul of
gdm which will be called gdm3 and which we expect to have in Ubuntu in
gutsy+1.  (The current gdm2 code isn't very pretty so this may well be
justified.)  Therefore any changes we make to gdm now will be thrown
away afterwards.

We have consolekit in Ubuntu universe, synced from Debian.  We also
have in our version of gdm2 the changes which are supposed to support
consolekit, although the latter are compiled out by default.  I have
tested this new functionality as it is current present in gutsy and it
doesn't work properly, but I haven't spent any significant effort
debugging it yet.

Our options would seem to be:

 1. Debug gdm's interaction with consolekit in gutsy.
 2. Disable fast user switching for gutsy and hope for consolekit
    to work better in gutsy+1.
 3. Press ahead with our own gdm-based implementation and expect to
    throw it away.

I don't think 3 is reasonable under the circumstances.
1 is plausible and 2 is a good fallback.

I haven't investigated in any detail how broken our consolekit/gdm
setup is, but it's possible that it will be straightforward to get it
working (or working well enough).  So that's what I propose to spend
at least some time on.

If anyone I haven't spoken to already has any knowledge about or
experience with consolekit particularly on Ubuntu please let me know.

One side issues to dispose of: Compiz can only be made to work on one X
server per machine.  This means that in any setup that doesn't involve
a working proxy server (which we don't currently have since our Xephyr
does not currently support the glx extension) only the first user to
log in gets the fancy desktop effects.

Ian.

[1] We discovered consolekit et al by having it demonstrated to us at
    Guadec on another distribution.  This new functionality is quite
    recent.



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