cat Xorg.8.log|grep -i nvidia

[   188.763] (++) Using config file: "/etc/bumblebee/xorg.conf.nvidia"
[   188.821] (**) |   |-->Device "DiscreteNvidia"
[   188.821] (++) ModulePath set to "/usr/lib/nvidia/xorg/,/usr/lib/xorg/modules"
[   194.882] (II) Loading /usr/lib/nvidia/xorg/modules/extensions/libglx.so
[   196.661] (II) Module glx: vendor="NVIDIA Corporation"
[   196.698] (II) NVIDIA GLX Module  340.24  Wed Jul  2 15:04:31 PDT 2014
[   196.698] (II) LoadModule: "nvidia"
[   196.699] (II) Loading /usr/lib/xorg/modules/drivers/nvidia_drv.so
[   196.867] (II) Module nvidia: vendor="NVIDIA Corporation"
[   196.891] (II) NVIDIA dlloader X Driver  340.24  Wed Jul  2 14:42:23 PDT 2014
[   196.891] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs
[   196.930] (II) NVIDIA(0): Creating default Display subsection in Screen section
[   196.930] (==) NVIDIA(0): Depth 24, (==) framebuffer bpp 32
[   196.930] (==) NVIDIA(0): RGB weight 888
[   196.930] (==) NVIDIA(0): Default visual is TrueColor
[   196.930] (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0)
[   196.930] (**) NVIDIA(0): Option "NoLogo" "true"
[   196.930] (**) NVIDIA(0): Option "ProbeAllGpus" "false"
[   196.930] (**) NVIDIA(0): Option "UseEDID" "false"
[   196.930] (**) NVIDIA(0): Option "UseDisplayDevice" "none"
[   196.931] (**) NVIDIA(0): Enabling 2D acceleration
[   196.931] (**) NVIDIA(0): Ignoring EDIDs
[   196.931] (**) NVIDIA(0): Option "UseDisplayDevice" set to "none"; enabling NoScanout
[   196.931] (**) NVIDIA(0):     mode
[   201.066] (EE) NVIDIA(GPU-0): Failed to initialize the NVIDIA GPU at PCI:1:0:0.  Please
[   201.066] (EE) NVIDIA(GPU-0):     check your system's kernel log for additional error
[   201.066] (EE) NVIDIA(GPU-0):     messages and refer to Chapter 8: Common Problems in the
[   201.066] (EE) NVIDIA(GPU-0):     README for additional information.
[   201.066] (EE) NVIDIA(GPU-0): Failed to initialize the NVIDIA graphics device!
[   201.066] (EE) NVIDIA(0): Failing initialization of X screen 0
[   201.066] (II) UnloadModule: "nvidia"

dmesg|grep NVRM

[  188.828166] NVRM: loading NVIDIA UNIX x86_64 Kernel Module  340.24  Wed Jul  2 14:24:20 PDT 2014
[  201.219294] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
[  201.246240] NVRM: RmInitAdapter failed! (0x25:0x28:1181)
[  201.246251] NVRM: rm_init_adapter failed for device bearing minor number 0
[  201.246271] NVRM: nvidia_frontend_open: minor 0, module->open() failed, error -5
[  838.231110] NVRM: request_irq() failed (-22)
[  838.231118] NVRM: nvidia_frontend_open: minor 0, module->open() failed, error -22
[  842.366114] NVRM: request_irq() failed (-22)
[  842.366122] NVRM: nvidia_frontend_open: minor 0, module->open() failed, error -22
[  860.463470] NVRM: request_irq() failed (-22)
[  860.463478] NVRM: nvidia_frontend_open: minor 0, module->open() failed, error -22