Hello everyone,
I'm running Kubuntu 12.04.2(KDE 4.8.5) and if I install OpenCL on this machine, the desktop effects just stop working. I'm running Intel's graphics adapter(Intel Corporation Ivy Bridge Graphics Controller (rev 09)) and the effects work fine if OpenCL is not installed/uninstalled. Could someone help me out here? Thank you!

how did you install OpenCL?

mgraesslin wrote:how did you install OpenCL?

I installed the package python-pyopencl via apt which installed the following packages:
blt freeglut3 libblas3gf libboost-python1.46.1 libglade2-0 liblapack3gf nvidia-current nvidia-settings pkg-config python-dateutil python-decorator python-glade2 python-matplotlib python-matplotlib-data python-numpy python-opengl python-pyopencl python-pyparsing python-pytools python-tk python-tz screen-resolution-extra tcl8.5 tk8.5 ttf-lyx.

probably your setup is now broken. As you can see it installed the NVIDIA driver, but you have Intel hardware.

Since pyopencl depends on nvidia drivers, I cannot prevent it from being installed. Is there some way where I could force KWin to ignore the fact that the nvidia related packages are installed and continue to render the graphic effects properly?

well that depends. If your setup is broken (you could check with glxinfo) there is not much to do. I personally doubt that OpenCL will work given that it installed the NVIDIA drivers.

Here's output of glxinfo with OpenCL installed: http://paste.kde.org/p26d01d61/. Here's output of glxinfo without OpenCL installed: http://paste.kde.org/p7df349ef/. I guess something is indeed broken?

well with OpenCL installed your GLX is broken. No application works, so it is not surprising that KWin doesn't work.

Can anything be done to fix GLX so that the desktop effects working fine?

arvindsraj wrote:Can anything be done to fix GLX so that the desktop effects working fine?

make sure that your system is configured correctly - follow the instructions by your distribution. E.g. ensure that the NVIDIA driver is not set in xorg.conf. But I need to point out again that OpenCL will not work if it pulls in the nvidia driver. This means it requires nvidia hardware, but you have intel hardware. So my recommendation would be to get an OpenCL software stack which doesn't require the nvidia driver.

Okay I'll look for a version that doesn't depend on nvidia and if that doesn't work, I'll try figure out if the effects of nvidia-* packages can be turned off. Thanks a lot mgraesslin!

arvindsraj wrote:Okay I'll look for a version that doesn't depend on nvidia and if that doesn't work, I'll try figure out if the effects of nvidia-* packages can be turned off. Thanks a lot mgraesslin!

Looks like it's an issue with Ubuntu and not KDE(Bug report: https://bugs.launchpad.net/ubuntu/+source/pyopencl/+bug/763457). It should be the amd opencl packages that should get installed. Sorry about the confusion! I'll contact Ubuntu about this.