NVidia GPU disappears after reboot

Recently I have installed Ubuntu Mate 15.10 on my Dell Inspiron 5720. This laptop (like many others) uses optimus technology and nvidia GeForce GT 630M GPU. My driver version is 358.09 from http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu .
When I switch to Intel card in nvidia-settings and restart my PC everything is fine, but when I try to restart it again with only intel enabled, then nvidia GPU disappears. Normally I can see it in the results of lspci:

$ lspci | grep 3D
01:00.0 3D controller: NVIDIA Corporation GF117M [GeForce 610M/710M/810M/820M / GT 620M/625M/630M/720M] (rev a1)

But after restart it disappears. The error from nvidia-settings is “Active graphics card: unknown”. The only way to bring it back is to power off the computer and then start it again - normal reboots don’t solve the problem.
This is very annoying problem, because I cannot use tools like bumblebee to switch these cards dynamically - it won’t work after restart. I wouldn’t mind using only nvidia, but it has this ugly tearing problem that is not fixed yet (https://devtalk.nvidia.com/default/topic/775691/linux/vsync-issue-nvidia-prime-ux32vd-with-gt620-m-/1). I have attached log files generated by nvidia-bug-report.sh. When nvidia card is gone, this shell script is also unavailable, I have prepared the log file using a copy of this script.
Previously I had Ubuntu 14.04 with many different versions of the driver and during 1.5 years of using it this problem happened once - but I just ignored it. On the new system it happens after every restart.

Normal start with nvidia gpu enabled: http://pastebin.com/mydiZVBV
First start on intel card (nvidia is still available): http://pastebin.com/XbgFZz00
Second start (nvidia is gone): http://pastebin.com/j1fd3ctt

Thanks in advance.

I have same issue.

I am software engineer and debugging my private program that uses NVIDIA’s GPU.

I see the “GPU disappears issue” while debugging OpenCL-OpenGL interoperability.
When I test my buggy programs, my computer sometimes freezes, and GPU disappears after soft reboot.
To recover my GPU, I have to do hard reboot (cold boot).

I’ve just ignored these issues because it is difficult to reproduce and report to this forum; however, I wish this issue would be fixed.

I use GTX 980 on x86_64 linux. The driver is 358.09.

If you want CUDA/OpenCL devices to work after a reboot add the following line to /etc/rc.d/rc.local:

# Create missing nvidia device nodes after reboot
/usr/bin/nvidia-modprobe -c 0 -u

I found that my PC had a problem in power supply.
My GPU board has two power connecters, but one of them is not well connected.
After I connected two cables properly, my issue seems to be solved.

Sorry for disturbing, but I wish my posts will help someone else.