не выключается дискретная карточка:

# uname -a

Linux lersobook 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u4 (2015-09-19) x86_64 GNU/Linux

# lspci | egrep 'VGA|3D'

00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)

01:00.0 VGA compatible controller: NVIDIA Corporation GK107M [GeForce GT 650M] (rev ff)

# optirun glxspheres64

[ 490.092235] [ERROR]Cannot access secondary GPU - error: Could not enable discrete graphics card

[ 490.092292] [ERROR]Aborting because fallback start is disabled.

# cat /proc/acpi/bbswitch

0000:01:00.0 OFF