You should read the changelog. nvidia-prime doesn't use bbswitch anymore, I don't know why. The changelog doesn't say.
It now uses the built-in kernel mechanism for turning off the nvidia card. Unfortunately, this method requires the nouveau driver and unfortunately you can't load the nouveau driver and the nvidia driver at the same time. Also, unfortunately the nvidia driver can't be unloaded without a reboot, due to a bug in logind, or at least without restarting logind. Somehow, this also means that the nvidia driver needs to be actually uninstalled, which means rebuilding initramfs to uninstall nvidia. And going back to nvidia (hybrid mode) now requires the nvidia driver to be reinstalled. It's a far cry from the old way. It's a bit of puzzle because bbswitch still works in the latest kernel and with the latest nvidia. But prime select is pretty complex, I haven't found another distribution where it has been ported, so there are probably good reasons for this. The dev says this approach is needed to work around gdm3 bugs, which I find ironic since I have never got gdm3 working with my nvidia laptops anyway (I use modeset=1 with the nvidia driver). -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to nvidia-prime in Ubuntu. https://bugs.launchpad.net/bugs/1765556 Title: nvidia-prime needs a reboot to switch between dGPU/hGPU Status in nvidia-prime package in Ubuntu: Confirmed Bug description: I previously used Ubuntu 16.04 and Nvidia 375 driver with a Nvidia Geforce 635M and Sandy Bridge i7. To switch between the 2 Optimus cards (Intel hybrid and Nvidia discrete), one had to go into nvidia- settings, switch, logoff, login back, and the change was applied. I now have a Nvidia Quadro M2000 and a Skylake Xeon which has some Sync/Mux feature (whatever does that mean) with the Nvidia 390 driver. First of all, installing nivida-prime doesn't install bbswitch-dkms. Then, once the GPU switch is made, it triggers update-initramfs, recompile the kernel modules, and one needs to reboot the system to get the GPU change. Even when we install bbswitch-dkms. So am I getting a wrong impression or is there something twisted here ? ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: nvidia-prime 0.8.7 ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15 Uname: Linux 4.15.0-15-generic x86_64 ApportVersion: 2.20.9-0ubuntu4 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Thu Apr 19 19:20:01 2018 Dependencies: InstallationDate: Installed on 2018-04-08 (11 days ago) InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180408) PackageArchitecture: all SourcePackage: nvidia-prime UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-prime/+bug/1765556/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
