I am running Xubuntu 16.04 on my Acer Aspire E5-573G laptop, which apparently uses Optimus and doesn't have a BIOS option to switch between integrated and discreet graphics. I followed this answer to try to get my NVIDIA GeForce 940M to work using nvidia-364. While I can use my card by executing # prime-select nvidia and relogging, Xorg crashes upon the next logout, reboot, or shutdown, even if I first execute # prime-select intel. Therefore, I'd like to use my card only through optirun (or primusrun; I haven't been able to find how the two differ).
The first time I try to use optirun, I receive the following error message:
$ optirun glxgears
Xlib: extension "GLX" missing on display ":8".
All subsequent times, I receive these:
$ optirun glxgears
[ 61.760218] [ERROR]Cannot access secondary GPU - error: [XORG] (EE)
[ 61.760244] [ERROR]Aborting because fallback start is disabled.
I haven't been able to find any leads on the first error message, but as for the second set, I found this answer, which I followed only to discover my /etc/bumblebee/xorg.conf.nvidia already had the correct line:
$ lspci|grep NVIDIA
04:00.0 3D controller: NVIDIA Corporation GM108M [GeForce 940M] (rev a2)
$ grep BusID /etc/bumblebee/xorg.conf.nvidia
# To get the BusID prop, run `lspci | egrep 'VGA|3D'` and input the data
BusID "PCI:04:00:0"
I also found a relevant thread, but adding acpi=force to the boot parameters did not solve the problem.
I've also tried nvidia-361; the system would not boot with acpi=force but otherwise exhibited the same issues as nvidia-364, nvidia-367, and nvidia-370 (all of which I've tried). Nouveau also emits the same error messages. For what it's worth, I've noticed leaving a 3D application running while not the focused window eventually crashes Xorg, regardless of whether it's using integrated or discreet graphics or even of if I have Bumblebee installed.
I realize NVIDIA provides terrible support for Optimus on Linux, but any help getting my card working reasonably well would be much appreciated. I know I could just uninstall Bumblebee and use integrated graphics, but that doesn't answer this question.
