Compiz fails to startup if "show icons on desktop" is disabled in KDE ("Error: Another window manager is already running")

[Daniel Hahler]

Binary package hint: compiz

I've used compiz from time to time in KDE by running "compiz --replace" (also during the late Gutsy development cycle), but now that I've tried it again (after a few days or weeks) on Ubuntu Gutsy, it fails:

$ compiz --replace
Checking for Xgl: not present.
Detected PCI ID for VGA: 05:00.0 0300: 10de:0140 (rev a2) (prog-if 00 [VGA])
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Comparing resolution (1920x1200) to maximum 3D texture size (4096): Passed.
Checking for nVidia: present.
Checking for FBConfig: present.
Checking for Xgl: not present.
Starting kde-window-decorator
/usr/bin/compiz.real (core) - Error: Another window manager is already running on screen: 0
/usr/bin/compiz.real (core) - Fatal: No manageable screens found on display :0.0

It does still work with Gnome. I've also rebooted already after noticing this problem.

[Daniel Hahler (blueyed)]

If I enable/define DEBUG for the build, I can see that the error from X is "BadAccess":
$ compiz --replace
Checking for Xgl: not present.
Detected PCI ID for VGA: 05:00.0 0300: 10de:0140 (rev a2) (prog-if 00 [VGA])
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Comparing resolution (1920x1200) to maximum 3D texture size (4096): Passed.
Checking for nVidia: present.
Checking for FBConfig: present.
Checking for Xgl: not present.
Starting kde-window-decorator
X Error of failed request: BadAccess (attempt to access private resource denied)
  Major opcode of failed request: 2 (X_ChangeWindowAttributes)
  Minor opcode of failed request: 0
  Resource id in failed request: 0x1a5
/usr/bin/compiz.real (core) - Error: Another window manager is already running on screen: 0
/usr/bin/compiz.real (core) - Fatal: No manageable screens found on display :0.0

[Daniel Hahler (blueyed)]

I've found the reason for this: http://forum.compiz-fusion.org/showpost.php?p=8369&postcount=8

If I disable "Show icons on desktop" in Settings->Desktop->Behavior (e.g. kcontrol), then it fails like documented above.

[Jonathan Thomas (echidnaman)]

Desktop icons are handled differently in KDE 4.1, so this isn't an Issue in Kubuntu Intrepid (8.10)
Thanks for the bug report.