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It provides a much simpler way to switch between GPU modes on Optimus Laptops under Linux, as well as turning off the Nvidia dGPU using an alternative approach that consists of removing the card from the PCI bus with Udev rules.

nvidia-gpu-off

The definitive guide to completely turn off your Nvidia dedicated GPU and thus doubling your laptop's battery life on Linux.

Preface

Nvidia GPUs on Linux have always been a headache due to their propietary drivers (obligatory reference?) but this problem is exacerbated on laptops due to inexistent dynamic power management technologies on pre-Turing cards paired with Intel processors older than Coffee Lake (official Nvidia documentation on dynamic PM for Turing and newer cards).

Why nouveau or bbswitch are NOT an alternative?

• The open-source nouveau driver built into the Linux kernel provides adequate dynamic PM and PRIME offloading functionality however due to restrictions imposed by Nvidia it can't control the graphics card clock speeds providing mediocre performance and it may cause software incompatibility issues (in my laptop opening GNOME settings app when running nouveau causes the entire desktop to hang for almost 5 seconds)

• bbswitch hasn't been updated since 2013 and is completely broken on some systems.

Requirements

• Having an Optimus laptop with a pre-Turing Nvidia graphics card.
• This guide was designed for Linux distributions using systemd as their init system.

Limitations

Your HDMI ports won't work if they're wired to the Nvidia GPU so please keep this in mind, however you can always reverse the procedures described in this guide.

Let's go!

1) Get rid of propietary Nvidia drivers

Please refer to your distribution's documentation to remove the Nvidia drivers however on Ubuntu you can do:

sudo apt-get autoremove --purge *nvidia*

Then reboot your system.

2) Get to know your PCI busses

Before proceeding with this guide we need to know which are the PCI busses employed by the Nvidia card, please run: lspci | grep NVIDIA

In my laptop this was the output:

01:00.0 VGA compatible controller: NVIDIA Corporation GP106M [GeForce GTX 1060 Mobile]
01:00.1 Audio device: NVIDIA Corporation GP106 High Definition Audio Controller

As you can see 01:00.0 belongs to the GPU itself and 01:00.1 to the GPU's audio chipset, let's take note of those PCI busses.

3.1) Install acpi-call-dkms

On Ubuntu, Debian and friends do:

sudo apt install acpi-call-dkms

On Arch Linux and friends this package is called acpi_call-dkms so do:

sudo pacman -S acpi_call-dkms

If your distro is not listed please refer to their respective documentation nor repositories.

3.2) Find an ACPI call that works for you

Before proceeding we need to:

sudo modprobe acpi_call

On Ubuntu, Debian and friends please run sudo /usr/share/doc/acpi-call-dkms/examples/turn_off_gpu.sh

For Arch Linux and friends run sudo /usr/share/acpi_call/examples/turn_off_gpu.sh

This was my output:

Trying \_SB.PCI0.P0P1.VGA._OFF: failed
Trying \_SB.PCI0.P0P2.VGA._OFF: failed
Trying \_SB_.PCI0.OVGA.ATPX: failed
Trying \_SB_.PCI0.OVGA.XTPX: failed
Trying \_SB.PCI0.P0P3.PEGP._OFF: failed
Trying \_SB.PCI0.P0P2.PEGP._OFF: failed
Trying \_SB.PCI0.P0P1.PEGP._OFF: failed
Trying \_SB.PCI0.MXR0.MXM0._OFF: failed
Trying \_SB.PCI0.PEG1.GFX0._OFF: failed
Trying \_SB.PCI0.PEG0.GFX0.DOFF: failed
Trying \_SB.PCI0.PEG1.GFX0.DOFF: failed
Trying \_SB.PCI0.PEG0.PEGP._OFF: works!
Trying \_SB.PCI0.XVR0.Z01I.DGOF: failed
Trying \_SB.PCI0.PEGR.GFX0._OFF: failed
Trying \_SB.PCI0.PEG.VID._OFF: failed
Trying \_SB.PCI0.PEG0.VID._OFF: failed
Trying \_SB.PCI0.P0P2.DGPU._OFF: failed
Trying \_SB.PCI0.P0P4.DGPU.DOFF: failed
Trying \_SB.PCI0.IXVE.IGPU.DGOF: failed
Trying \_SB.PCI0.RP00.VGA._PS3: failed
Trying \_SB.PCI0.RP00.VGA.P3MO: failed
Trying \_SB.PCI0.GFX0.DSM._T_0: failed
Trying \_SB.PCI0.LPC.EC.PUBS._OFF: failed
Trying \_SB.PCI0.P0P2.NVID._OFF: failed
Trying \_SB.PCI0.P0P2.VGA.PX02: failed
Trying \_SB_.PCI0.PEGP.DGFX._OFF: failed
Trying \_SB_.PCI0.VGA.PX02: failed

As you can see \_SB.PCI0.PEG0.PEGP._OFF was the right ACPI call for my laptop so please take note of yours.

4) Blacklist nouveau and load acpi-call-dkms

Edit the /etc/modprobe.d/blacklist.conf and append the following at the end of the file:

blacklist nouveau

Edit /etc/modules and append acpi_call at the end of the file.

5) Turn off your GPU at startup

For autostart we'll be using systemd-tmpfiles.

Edit /etc/tmpfiles.d/acpi_call.conf and append:

w /proc/acpi/call - - - - \\_SB.PCI0.PEG0.PEGP._OFF

Please replace \_SB.PCI0.PEG0.PEGP._OFF with the ACPI call you got on step 3.2 but don't forget to escape the backslash.

Now rebuild your initrams with sudo update-initramfs -u -k all and reboot.

6.1) Try to remove those PCI busses

After rebooting your Nvidia GPU should have been turned off by the ACPI call but the failure to remove its PCI busses may lead to stability issues so do the following for each one the busses you got on step 2.

echo 1 > /sys/bus/pci/devices/[PCI bus here]/remove

For my laptop I had to do:

sudo su
echo 1 > /sys/bus/pci/devices/0000\:01\:00.0/remove
echo 1 > /sys/bus/pci/devices/0000\:01\:00.1/remove

Be careful with backslashes.

Now you can re-run lspci to check that NVIDIA is no longer present on our system.

6.2) Remove PCI busses at startup

Edit /etc/tmpfiles.d/remove_gpu_from_lspci.conf and append the following for each one of your Nvidia busses:

w /sys/bus/pci/devices/[PCI bus here]/remove - - - - 1

For my laptop it was:

w /sys/bus/pci/devices/0000\:01\:00.0/remove - - - - 1
w /sys/bus/pci/devices/0000\:01\:00.1/remove - - - - 1

As a precautionary step I rebuilt my initramfs before rebooting again.

Results

My laptop's power consumption went down from 30W watching a Youtube video with propietary drivers on-demand mode to just 10W after following this guide according to powertop.

I hope this guide may help you :D