Comment 38 for bug 1758243

@Pete:

Yes, more recent kernels now can automatically power down the nvidia card off when it's not in use, so you don't need bbswitch anymore.

What's even more cool is that with the nvidia 435.21 driver and the version of X that comes with Ubuntu 19.10, you don't even need bumblebee any more: if you enable nvidia load-on-demand in nvidia-settings, you get an intel desktop with the nvidia card pretty much powered down but you can run any application using the nvidia card by exporting these variables first:

export __NV_PRIME_RENDER_OFFLOAD=1
export __GLX_VENDOR_LIBRARY_NAME=nvidia

Of course, when the application finishes, the kernel powers down the nvidia card again.

VUlkan is also very cool: I export this variable as well to ensure it gets used for the nvidia card:

export __VK_LAYER_NV_optimus=NVIDIA_only