Compositing has been suspended by another application. Eek!

After the latest round of updates to Slackware64 13.1, compositing died on my machine. The first thing I noticed is that my windows no longer wobbled.

When I checked in System Settings -> Desktop -> Desktop Effects, I saw that “Compositing has been suspended by another application . . .” I clicked the Resume Compositing button, but once again received the message and found that “Compositing is temporarily disabled.”

After a bit of searching, I found a post on the KDE Community Forums where a Kubuntu user had solved this issue by checking Disable functionality checks on the Advanced tab. Figuring it was worth a try, I checked the box and clicked the Apply button.  Oops! My desktop became pale blue nothing!

Using the CTRL+ALT+BACKSPACE key combination, I shut down X.  Then, from the shell, I poked around my .kde directory and found the setting in .kde/share/config/kwinrc as “DisableChecks=true.” So, I removed this line from the file and started X once more: still no compositing; no effects, but at least I had usable KDE. (See: there’s a good reason I don’t start the GUI automagically!)

At this point I was mildly frustrated. I couldn’t understand why upgrading Xorg server to 1.7.7 killed compositing. Heck, maybe was it the newly installed kdegraphics-4.4.3!?! Did I really want to fuss with reverting packages until the problem went away? Nope!

I figured it was time to punt, so I downloaded and installed the latest nVidia driver–as much to give my self something to do as in hopes that it would fix the problem. Once the driver was installed, I logged out as root and logged back in as myself.  Now the moment of truth! I typed startx and pressed my well-worn ENTER key. OMG! It worked! I have wobbly windows again!

So, time to check this on the MacBook which uses an nVidia 9400M. Same results: no compositing after the upgrade and upgrading the nVidia driver fixed the issue.

The TL/DR of it all is: If upgrading Slackware kills your nVidia card’s compositing, just update the nVidia driver to 256.44 and life is good!

Happy Hacking!
Stu…

P.S. I was previously using nVidia driver version 256.35.

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