today, my NVidia graphics card gave up. I removed it from my computer and switched to the on-board one:
$ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)
I have two systems on this computer: One is Kubuntu 15.04 which used the nouveau driver, before (and never used the proprietary nvidia driver). The other one is a Kubuntu 15.10 which used the proprietary nvidia-352 driver before.
After the removal of the NVidia driver, my Kubuntu 15.04 booted without any trouble and X works fine with two monitors attached and with all 3D effects. I really do not need an NVidia card.
However, the Kubuntu 15.10 does not work properly. First, X didn't start at all. So I logged in to the text console (which was fortunately working fine) and I uninstalled all nvidia driver stuff:
$ apt-get purge nvidia-*
After this, I rebooted and the system still didn't work :-( I found out that the problem was a wrong 'xorg.conf'. It stated (among other things):
Section "ServerLayout" Identifier "layout" Screen 0 "nvidia" Inactive "intel" EndSection Section "Device" Identifier "intel" Driver "modesetting" BusID "PCI:0@0:2:0" Option "AccelMethod" "None" EndSection
I removed the 'Inactive "intel"' line, changed the "nvidia" to "intel" and invoked startx => got a graphical system. I rebooted and the file was wrong again.
After some digging, I found that I have to pass 'nogpumanager' to the kernel, hence I edited '/etc/default/grub', ran 'update-grub' and rebooted => the system booted fine.
However, I saw that some of the desktop effects - e.g. the cube - don't work (they work fine in my Kubuntu 15.04).
The problem seems to be that X uses the 'modesetting' driver instead of the 'intel' driver. I tried to explicitly set 'Driver "intel"' in my 'xorg.conf', but then X does not start :-(
When I run 'Xorg -configure', however, it lists 'intel' as the first line under 'List of video drivers:'!
I assume that my previous installation of the nvidia proprietary driver somehow somewhere forced the intel driver out of the way. However, even after hours of searching, I still didn't find where this problem is located.
In which file does it suppress the intel driver?!
Please help! I really don't want to re-install the system, just because the nvidia driver left some garbage behind (that I was unable to find, so far). And I really would like to use the cube and many other 3D effects again ;-) They seem to be automatically suppressed when using XRender (instead of OpenGL). And I seem not to be able to enable OpenGL when not using the proper driver, even though 'glxinfo' says:
$ glxinfo | grep OpenGL OpenGL vendor string: VMware, Inc. OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.6, 256 bits) OpenGL version string: 3.0 Mesa 11.0.2 OpenGL shading language version string: 1.30 OpenGL context flags: (none)
Also, test programs like 'glxgears' work fine (and even say, I had 2500+ FPS).
Best regards, Marco :-)