Upgrade from 16.04 to 18.04, then uninstalling unity disables hardware acceleration

Status changed to 'Confirmed' because the bug affects multiple users.

Similar problem. I actually had updated to 18.04 beta, with no problems. The issue manifested itself after I upgraded to the final release yesterday. I don't think it's related to similar other bugs as I have libegl-mesa0 . I also cannot find any error message in the logs, seems that Xorg loads all of the HW acceleration libraries just fine, but for some reason gnome-shell runs on llvmpipe.

Running on a live evaluation gets proper HW acceleration, but I'd really rather avoid having to reinstall if it can be avoided. A pointer for where to look for trouble would be much appreciated, all of the obvious log files show no sign of trouble.

Same thing here.
The Intel driver ils not even loaded.
Evrything is slow and external displays are not detected.

Ok I fixed the problem on my system. This has nothing to do with libglvnd but I don't know to which package it should be attributed. Problem (at least for me) seems to be linked to

/etc/X11/Xsession.d/50_check_unity_support

that fails (as I had uninstalled unity after update) and causes Xsession to fall-back on LLVMPipe.
Remove or comment that file and accelerated drivers are back

OpenGL renderer string: Mesa DRI Intel(R) HD Graphics 520 (Skylake GT2)

Hope this helps, and that someone more experienced can tag the appropriate package so that the update removes this leftover check.

@Michele: Thanks, that's it. You're my personal hero of the week (-:

I'd like to confirm that I observed this same problem when upgrading from 17.10 to 18.04. Removing /etc/X11/Xsession.d/50_check_unity_support also fixed my installation.

Does not solve the problem for me, still Intel VGA driver not loaded.

`lspci -v` returns :

00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06) (prog-if 00 [VGA controller])
        Subsystem: Dell 4th Gen Core Processor Integrated Graphics Controller
        Flags: bus master, fast devsel, latency 0, IRQ 11
        Memory at f5800000 (64-bit, non-prefetchable) [size=4M]
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at f000 [size=64]
        [virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
        Capabilities: [90] MSI: Enable- Count=1/1 Maskable- 64bit-
        Capabilities: [d0] Power Management version 2
        Capabilities: [a4] PCI Advanced Features

No driver is loaded.

And `lsmod` does not show the intel video driver.

Am I missing something?

Also lshw reports VGA controller as *unclaimed*.

sudo lshw -c display ~
  *-display UNCLAIMED
       description: VGA compatible controller
       product: 4th Gen Core Processor Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 06
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list
       configuration: latency=0
       resources: memory:f5800000-f5bfffff memory:e0000000-efffffff ioport:f000(size=64) memory:c0000-dffff

The xorg intel package is installed:

Package: xserver-xorg-video-intel
Version: 2:2.99.917+git20171229-1

Maybe related to this other bug report:
https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1768232

I had to use a 4.16 kernel from http://kernel.ubuntu.com/~kernel-ppa/mainline to have a working machine!

I reproduced the bug with the following:
* 17.10 itself upgraded from 17.04
* uninstalled Unity (to workaround a bug but I don't remember which one)
* upgrade to 18.04 today

-> hardware acceleration disabled

lspci:
> 00:02.0 VGA compatible controller: Intel Corporation Device 5a85 (rev 0b)

The workaround described in #6 worked like a charm for me.

I had exactly the same issue. Commenting out the content of /etc/X11/Xsession.d/50_check_unity_support works around the issue.

@Michele - Thanks, that did it for me. This problem has been driving me nuts since I upgraded to 18.04.

I went one step further though. I noticed that file belonged to the nux-tools package. I went ahead and ran "sudo apt purge nux-tools". I didn't see a need to keep that package around anymore. No other packages were depending on that package either.

lspci:
00:02.0 VGA compatible controller: Intel Corporation Device 5927 (rev 06)

The mentioned file,/etc/X11/Xsession.d/50_check_unity_support, should only run on systems using Xubuntu. Is that what everyone is using?

Additionally, I tried to recreate this by uninstalling unity but unity_support_test still passes for me.

[ 1:24PM 10282 ] [ bdmurray@impulse:~/source-trees/metarelease/ubuntu ]
 $ /usr/lib/nux/unity_support_test; echo $?
0
[ 1:24PM 10283 ] [ bdmurray@impulse:~/source-trees/metarelease/ubuntu ]
[ 1:24PM 10285 ] [ bdmurray@impulse:~/source-trees/metarelease/ubuntu ]
 $ sudo apt-get remove unity
[sudo] password for bdmurray:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  gtk3-nocsd libgtk3-nocsd0 python3-feedparser session-shortcuts unity-scope-calculator unity-scope-chromiumbookmarks unity-scope-colourlovers
  unity-scope-devhelp unity-scope-firefoxbookmarks unity-scope-home unity-scope-manpages unity-scope-openclipart unity-scope-texdoc
  unity-scope-virtualbox unity-scope-yelp unity-scope-zotero unity-scopes-master-default
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
  unity unity-session unity-tweak-tool
0 upgraded, 0 newly installed, 3 to remove and 13 not upgraded.
After this operation, 9,766 kB disk space will be freed.
Do you want to continue? [Y/n] Y
[ 1:25PM 10286 ] [ bdmurray@impulse:~/source-trees/metarelease/ubuntu ]
 $ /usr/lib/nux/unity_support_test; echo $?
0

Is the unity_support_test failing for you all?

I'm using Ubuntu, not Xubuntu. I never tried to manually execute the script. I simply removed the file and rebooted – problem gone.

I have purged nux-tools (which removed the Xsession file), but I'm still rendering on llvmpipe

echo $LIBGL_ALWAYS_SOFTWARE gives me 1. Why?

@Brian: just FYI, the /etc/X11/Xsession.d/50_check_unity_support file is actually checking for ubuntu, not xubuntu: if [ "x$DESKTOP_SESSION" = "xubuntu" ] will be true if $DESKTOP_SESSION is "ubuntu", because it's prepending "x" to $DESKTOP_SESSION.

My unity_support_check was failing (it returns 1) so LIBGL_ALWAYS_SOFTWARE was being set to one. However, after I removed the /etc/X11/Xsession.d/50_check_unity_support file and reboot, LIBGL_ALWAYS_SOFTWARE is not set but I still get a llvm_pipe session.

This bug looks a lot like #1752938, which is about losing hardware acceleration but without removing unity.

I had these exact same symptoms today with my nVidia GTX 960 after doing a platform upgrade from 17.10 to 18.04.

Issue was actually dead simple to fix, the upgrade to 18.04 removed some PPAs (including the graphics drivers), so although the nVidia driver package was present on the system it wasn't getting updates and the system appears to have selected a software only driver to use instead. All I did was uninstall nvidia-390 using apt, re-added the ppa, apt-get updated, then reinstalled nvidia-390 again using apt. Fixed it fine for me.

###
sudo apt-get autoremove nvidia-390
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get update
sudo apt-get install nvidia-390
###

hope this is useful :)

I have witnessed a _related_ issue but it does not appear to be precisely the same problem.

https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1853585