Nouveau blacklisted but loaded

Hi I am trying to use Ubuntu-Prime for ubuntu 18 on an asus laptop with 2 GPU (intel & nvidia).

I found the power consumption of the computer to be way too high when I reboot with only the intel GPU (using prime-select intel or using nvidia-settings).

I found that the nouveau driver was loaded despite normally not used:

$ gpu-manager | grep nouveau
Is nouveau loaded? yes
Is nouveau blacklisted? yes
Skipping "/dev/dri/card1", driven by "nouveau"
Skipping "/dev/dri/card1", driven by "nouveau"
Found "/dev/dri/card1", driven by "nouveau"
Skipping "/dev/dri/card1", driven by "nouveau"

I tried to blacklist it and also have a kernel startup option to prevent nouveau from being loaded yet it still loads. This seems very un-linuxy to me.

I found a way to disable nouveau and get my battery life back when using prime with intel graphic card:

2 bugs in Ubuntu 18 are concerned:

1. Prime fails to turn off discrete GPU (known issue).

   Make sure that your discrete GPU is connected to PCI port 0000:01:00.0 (using lspci -vnn | grep '\''[030[02]\]' for instance)

   Change /etc/systemd/system/display-manager.service.wants/nvidia-prime-boot.service and replace the current execstart (referencing vgaswitcheroo which is not usually available by ExecStart=/bin/sh -c "echo 'auto' > '/sys/bus/pci/devices/0000:01:00.0/power/control'")

2. nvidia-fallback loads nouveau when nvidia is not loaded

   Even if we are willing not to use the discrete gpu !

   Disable the following service which loads nouveau driver when nvidia driver is not loaded : sudo systemctl disable nvidia-fallback.service