after switch user and login back, ume-launcher stop working

[Jouston Huang]

Steps to reproduce:

 * boot up and see ume-launcher working
 * switch user
 * login back
 * ume-launcher stop working

Expected: ume-launcher works like it was.

[Bill Filler (bfiller)]

After investigating, there are two main problems here:
1)Create a second user, and use Quit->Switch User to switch to this user. A second instance of the launcher is run as the new user and the original launcher instance is still running. The second launcher works, but the performance is extremely bad - everything on the system is very slow and sluggish. I'm guessing because we are consuming too many resources (memory, vram, ?). So the question is can Switching users be detected and can we release resources from the non-active instance of the launcher or somehow fix the performance issue?

2)The second case is to try Quit->Switch User and then log back in as the same user. This causes the same problem as suspend/resume (see bug 237761) where the launcher is no longer responsive to mouse events (key events still work). According to mterry, Switch User creates a new virtual terminal which is why we see the same symptoms here. Is there a way to have a generic "virtual terminal" listener that can perform the workaround that we do for suspend/resume?

[Neil J. Patel (njpatel)]

After fruther investigation, it seems that the Intel drivers cannot accelerate GL on additional virtual terminals.

This effects the performance of any gl-based application (try glxgears on the 2nd user). Killing the launcher on the 1st user before switching makes no difference.

[Bill Filler (bfiller)]

The plan is to disable switch user functionality when in Netbook mode as there is no workaround to the problem at this time. Switch User will still be enabled when in Classic Mode.

[Michael Terry (mterry)]

Fixed in desktop-switcher 0.2ubuntu5netbook0unr3. In classic mode, we enable user switching; in Netbook mode, we don't. The default was changed to 'disable user switching' in ume-config-netbook 0.20.