"[ 15.627194] vgaarb: this pci device is not a vga device" and problems related with bri

Hello there! My problem is probably related with switching cards configuration.

In dmesg I get warns the same as the name of topic.
I’m using Gentoo x64 and there is information which won’t be inside bugreport generated in nvidia archive:
emerge --info:
Some installed apps and version:

[ebuild   R    ] media-libs/mesa-11.0.6::gentoo  USE="bindist classic dri3 egl gallium gbm llvm nptl udev vdpau xa -d3d9 -debug -gles1 -gles2 -opencl -openmax -osmesa -pax_kernel -pic (-selinux) -vaapi -wayland -xvmc" ABI_X86="32 (64) (-x32)" VIDEO_CARDS="ilo intel (-freedreno) -i915 -i965 -nouveau -r100 -r200 -r300 -r600 -radeon -radeonsi -vmware" 0 KiB
[ebuild   R    ] x11-base/xorg-server-1.17.4:0/1.17.4::gentoo  USE="glamor ipv6 kdrive nptl suid udev xorg -dmx -doc (-libressl) -minimal (-selinux) -static-libs -systemd -tslib -unwind -wayland -xephyr -xnest -xvfb" 0 KiB
[ebuild   R    ] x11-misc/bumblebee-3.2.1::gentoo  USE="bbswitch" VIDEO_CARDS="nvidia -nouveau" 140 KiB
[ebuild   R    ] x11-drivers/nvidia-drivers-361.28:0/361::gentoo  USE="X acpi driver gtk3 kms multilib tools -pax_kernel -static-libs -uvm" 0 KiB
[ebuild   R   ~] x11-misc/primus-20150328::sabayon [20150328::jorgicio] ABI_X86="(64) -32 (-x32)" 0 KiB

Additional settings:

eselect opengl list

Available OpenGL implementations:
  [1]   nvidia *
  [2]   xorg-x11

eselect opencl list

Available OpenCL implementations:
  [1]   nvidia *

I don’t use 367.27 version, because I’ve got the same problem as there:
and it’s not related with my problem, because I had the same with 367.27.

Link to the report can be found there:

Next thing is when I change brightness in my laptop, I’ve got bugged brightness bar which looks the same like in this case:
Is that warning in dmesg really important and if it is, how could I fix this?

Please, help me.