Can anyone tell me if I’m on the right track here?

Drivers are loaded as or via kernel modules, right, and at installation the relevant modules are configured to be loaded at boot. So whatever modules I load, the hardware will simply work.

I am using Bumblebee for my nVidia Optimus, and the Intel gfx driver which is considered the main graphics driver of course and the nVidia driver is also loaded. So the question is, if I switch the BIOS back to nVidia only, the nvidia module should load and it should just work?

Last time I tried this (a while back) it somehow borked the setup for the nvidia driver.

I want to be able to use either optimus or nvidia only, because external monitors don’t work very well with optimus (but I did manage to get them to work) and I have been on a client site doing loads of meetings and presentations.

Drivers can be compiled directly (monolithic) into the kernel or loaded as modules, the detection of the hardware and the loading of the appropriate modules (if they have been compiled) can be handled by something like udev, however to be 100% of loading the correct ones there will usually be a file in etc/ of a sub dir of it for example conf.d/ containing the name of the modules to be loaded, also there could be another file that will contain config parameters to be passed to the modules as they are loaded.

Last time I tried this (a while back) it somehow borked the setup for the nvidia driver.

Probably cos of the bumblebee setup. Save your config files, switch to nvidia only and remove bumblebee/reinstall nvidia drivers.

I’ve never really got on with it, I just stick with nVidia only. The battery life gains are relatively minimal with the onboard as the nvidia GPU clocks down quite well, combined with the fact that a lot of my work needs the GPU it’s just not worth the faff.

Depends on your machine, but on my dell precision the GPU gets the core clock halved on battery anyway* thus saving power.

*at a low level, and I can’t override it, which is actually a PITA as sometimes I need all the gpu power but don’t want to plug in!

What h/w are you using Lenovo T4xx?

I had an issue on my T420 where if I set a combination of certain BOIS settings the external display failed to work under Linux. There appears to be some conflict with certain combinations of video and virtualisation settings. On the virtalisation settings in the BOIS I had to deselect the lower of the two options, VT-x I think it was, doing this from memory as not in a position to reboot at the moment and check. With that deselected I could use any graphics setting ok.

Well, I tried it anyway. Bumble does need to be disabled because it unloads nvidia.

But what I don’t understand is how X searches for drivers. It finds nvidia, but the module is actually called nvidia_331 so modprobe nvidia does not work. If that is the name of the module then why is X looking for something else?

I think maybe I will try wiping bumblebee and going with nvidia, but I did enjoy 6hr battery life.

In etc/modprobe.d/ is there an nvidia.conf file there? If so is there an alias line within it? where nvidia will be an alias for the driver

There are files, but no alias. Somehow X is finding nvidia to try and load, but the alias isn’t there.

I tried adding the alias, but no joy.