Re: debug X errors?

[Owen Taylor <otaylor redhat com>]

On Sun, 2010-08-29 at 13:38 -0700, Luis Villa wrote:
> Hey, guys-
> The latest stuff is looking pretty nice, but unfortunately it is also
> crashing pretty regularly for me, with errors like the following:
> 
> Bug in window manager: Unexpected X error: BadDrawable (invalid Pixmap
> or Window parameter) serial 26638 error_code 9 request_code 136
> minor_code 4) Shell killed with signal 6

This, I'm pretty sure is fixed by:

 http://bugzilla.clutter-project.org/show_bug.cgi?id=2303

In general, the two things that are useful to debug X errors:

 * A backtrace obtained by:

   - ssh in to the computer from a second computer
   - Run 'gnome-shell --replace --sync -g'
   - (gdb) r
   <reproduce crash>
   - (gdb) backtrace

 * Reproduction instructions

> Any pointers on how to debug those? Also, is there any way to
> automatically restart shell instead of falling back to metacity when
> this kind of thing happens?

What gnome-shell does on fatal exit is to restore to your configured
GNOME environment - so if you configure gnome-shell (if you have system
packages and use desktop-effects to switch to it), then the fallback
will be to gnome-shell.

For gnome-shell as jhbuild, the following *may* work:

 ln -s ~/gnome-shell/install/share/applications/gnome-shell.desktop \
       ~/.local/share/applications/
 gconftool -s -t string \
       /desktop/gnome/session/required_components/windowmanager \
       gnome-shell

 (untested, may either not work entirely, or may contain typos that 
  make it not work)

Offhand, it doesn't look to me like what Milan suggested with the
link to autostart will work for this purpose, though it's a method
I've suggested previously for making jhbuild gnome-shell the default.

- Owen