Whenever the X driver produces this error,
(EE) NVIDIA(0): Failed to initialize the NVIDIA graphics device!
it means the kernel module failed to initialize and you need to check your system log for a more detailed error message. A bug report includes all the relevant logs, in addition to detailed information about your configuration. When you have any
problem, whether you think it's a driver bug or not, including an nvidia-bug-report.log saves everybody time.