Feature request: modify bumblebee to unload nvidia modules if power management is done by the kernel

[Rocko]

It would be great to implement something like feature request bumblebee#978 (https://github.com/Bumblebee-Project/Bumblebee/issues/978), because bbswitch doesn't work with later kernels unless you disable pci power management at boot with pcie_port_pm=off added to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub (see https://github.com/Bumblebee-Project/bbswitch/issues/140 for more details) and in fact later kernels automatically activate and suspend the card as required, replacing the functionality of bbswitch.

To confirm this, I tried modifying the Ubuntu bumblebee source package, but it fails to build in Cosmic on my laptop with a number of reference errors like so (even though I do have libkmod2 installed):

/usr/bin/ld: src/module.o: in function `module_is_loaded':
/home/rocko/src/bumblebee-3.2.1/src/module.c:46: undefined reference to `kmod_module_new_from_name'

So I modified the bumblebee develop branch from git (https://github.com/Bumblebee-Project/Bumblebee/tree/develop) with the attached patch and built it to confirm that bumblebee works when allowing the kernel to manage power management. The most relevant part of the patch is this:

@@ -227,8 +228,12 @@ static void switch_and_unload(void)
   char driver[BUFFER_SIZE];

   if (bb_config.pm_method == PM_DISABLED && bb_status.runmode != BB_RUN_EXIT) {
- /* do not disable the card if PM is disabled unless exiting */
- return;
+ /* RR: unload the driver loaded by the graphics card */
+ bb_log(LOG_INFO, "PM disabled, unloading nvidia drivers anyway\n");
+ if (pci_get_driver(driver, pci_bus_id_discrete, sizeof driver)) {
+ module_unload(driver);
+ }
+ return;
   }

   //if card is on and can be switched, switch it off

but I have also included changing configuration defaults like PM_METHOD=none and setting up the Ubuntu library paths for nvidia and primus in Ubuntu 18.04/18.10 (see https://bugs.launchpad.net/ubuntu/+source/bumblebee/+bug/1758243 for why).

Then I configured and built it with:

autoreconf -f
./configure CONF_DRIVER=nvidia CONF_DRIVER_MODULE_NVIDIA=nvidia CONF_PM_METHOD=none \
      CONF_LDPATH_NVIDIA=/usr/lib/x86_64-linux-gnu:/usr/lib/i386-linux-gnu \
      CONF_MODPATH_NVIDIA=/usr/lib/x86_64-linux-gnu/nvidia/xorg,/usr/lib/xorg/modules,/usr/lib/xorg/modules/input \
      --prefix=/usr --sysconfdir=/etc
make clean
make && sudo make install

I disabled bbswitch via /etc/modprobe.d/bbswitch:

blacklist bbswitch

and then on reboot, optirun seems to be working fine:

$ optirun glxinfo|grep NVIDIA
server glx vendor string: NVIDIA Corporation
OpenGL vendor string: NVIDIA Corporation
OpenGL core profile version string: 4.6.0 NVIDIA 396.54
OpenGL core profile shading language version string: 4.60 NVIDIA
OpenGL version string: 4.6.0 NVIDIA 396.54
OpenGL shading language version string: 4.60 NVIDIA

and afterwards, the nvidia card is turned off:

$ cat /sys/bus/pci/devices/0000\:01\:00.0/power/runtime_status
suspended

This works even after a suspend/resume cycle.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: bumblebee 3.2.1-17 [modified: usr/bin/bumblebee-bugreport usr/bin/optirun usr/sbin/bumblebeed usr/share/doc/bumblebee/README.markdown]
Uname: Linux 4.19.0-041900rc3-generic x86_64
ApportVersion: 2.20.10-0ubuntu9
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Tue Sep 11 13:30:22 2018
InstallationDate: Installed on 2017-08-16 (390 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
SourcePackage: bumblebee
UpgradeStatus: Upgraded to cosmic on 2018-08-15 (26 days ago)
mtime.conffile..etc.bumblebee.bumblebee.conf: 2018-09-10T12:33:56.368908
mtime.conffile..etc.bumblebee.xorg.conf.nvidia: 2018-09-10T12:33:56.368908

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "bumblebee-git-develop.diff" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

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