Created attachment 141734 [details]
kernel log

Overall, nouveau works without problem in managing discrete GPU PM, and if I
check power consumption using powertop on a fresh boot it reports an average
battery discharge rate of ~7W like always.
After I resume the laptop from suspend, /sys/kernel/debug/vgaswitcheroo/switch
reports that the device is
dynamically turned off:

0:IGD:+:Pwr:0000:00:02.0
1:DIS: :DynOff:0000:01:00.0

But if I check with powertop, I get a battery discharge rate of ~11W. To better
identify the problem, I tried using bumbleebee+bbswitch+nvidia-driver and see
what bbswitch module reports. On a fresh boot, it works
ok as the nouveau driver, but after resuming from suspend
/proc/acpi/bbswitch reports that the card is turned ON, and there is no way to
power it off:

[root@example user]# cat /proc/acpi/bbswitch 
0000:04:00.0 ON
[root@example user]# tee /proc/acpi/bbswitch <<<OFF
OFF
[root@example user]# cat /proc/acpi/bbswitch 
0000:04:00.0 ON

I attached the kernel log using following parameters when using only nouveau
driver (no bumblebee/bbswitch/nvidia): log_buf_len=1M nouveau.debug=debug.

System specs:
Asus Vivobook S551LN
Intel i7 4500U
NVIDIA 840M
Archlinux 4.18.9-arch1-1-ARCH (but affecting older versions, since early 4.x
version when i started using linux)