Comment 156 for bug 1803179

After hours of experimenting on this laptop :

Computer : PC Specialist OptimusIX 15 (aka Clevo N8xxEP6)
BIOS : American Megatrends 1.07.13
OS : Arch Linux
GPU : NVIDIA GTX 1060 Mobile

Until recently, any attempt to use bumblebee or acpi commands to power down the GPU have resulted in a system freeze with lspci, suspend, power cable plug in, etc. No kernel line parameters seem to have any effect.

I have discovered that the system freeze is closely linked to the interaction between the nvidia graphics card on pci address 0000:01:00.0 and its associated sound card at pci address 0000:01:00.1 (I don't actually know what that sound card is doing - I presume it's for the HDMI port?)

If I completely disable the audio card using :
echo 1 | sudo tee /sys/bus/pci/devices/0000:01:00.1/remove

Then the system hangs are completely cured - I can acpi _OFF or _ON or _PS3 or _PS0 to my hearts content and the gfx card will power up and down perfectly, lspci behaves perfectly normally (without any lag), and suspend/resume and power cable plug/unplug all works. Even better, kernel power management on the PCI bus seems to work perfectly too, but only kicks in when I rmmod nvidia. So far, bumblebee and bbswitch also seem to be totally happy.

Can anybody else confirm similar findings?

Bear in mind that the audio card needs to be removed BEFORE the kernel loads any audio modules. I do it like this :

[Unit]
Description=Nvidia Audio Card OnBoot Disabler
Before=bumblebeed.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/sh -c "echo 1 > /sys/bus/pci/devices/0000:01:00.1/remove"
ExecStop=/usr/bin/sh -c "echo 1 > /sys/bus/pci/rescan"

[Install]
WantedBy=sysinit.target