How to debug session startup issues?

Asked by Rob Taylor on 2011-03-23

It's really quite tricky debugging session start issues, and poorly documented. I'm going to tell you some tricks in the answer to this question.

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Ubuntu gnome-session Edit question
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Rob Taylor
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Is this a question or are you going to answer your OWN question. If you intend to answer your own question please post as a how to on the ubuntu forums, not here.

if you have a question, please give details of what you are experiencing and we can assist.

Rob Taylor (robtaylor) said : #2

So, something isn't starting up correctly in your session, and you want to know how to go about debugging it.

Here are some tips and tricks -

1) edit /usr/share/xsession/gnome.desktop (or any of the others there if your issue is with other gnome-session based desktop environments, e.g. gnome-classic)
 - change
Exec=gnome-session --debug

2) restart gdm using
sudo service gdm restart

3) log into your account

4) read the woes and tribulations of gnome-session in ~/.xsession-errors

Note that the stdout and stderr of any programs launched by gnome-session will also appear in this log. If you know your app that's having issues has a debug mode, you can usually edit it's .desktop file (usually found in /usr/share/applications or /etc/xdg/autostart) to add a debug flag to it's Exec line, just like we did for gnome-session.

Happy hunting!

Rob Taylor (robtaylor) said : #3

@actionparsnip: oh rly? I'm not sure ubuntu forums is the place for deep debugging howtos. Then again neither is here. We so need :P

yes there are tonnes of how tos on the forums and that is the place for them. I suggest you read ANY of the other posts to see what these pages are for.

Rob Taylor (robtaylor) said : #5

@actionparsnip: I do and have, this isn't user-facing stuff, it's for devs. Jorge Castro suggests Stack Overflow as the best place nowadays.