vgaarb: this pci device is not a vga device : driver message

I sometimes get this vgaarb: this pci device is not a vga device in dmesg. The screen flashes a lot at boot, and at times I can booted into tty. Then I can ctrl+alt+f7 to get a desktop environment. Output of dmesg:

Any guesses guys? similar problems

Other details:

1. Output of lspci and /var/log/Xorg.0.log .
2. Output of lshw

VGA card:

$ lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation Sky Lake Integrated Graphics (rev 07) 

OS and kernel:

 ~  lsb_release -a No LSB modules are available. Distributor ID: neon Description: KDE neon User Edition 5.8 Release: 16.04 Codename: xenial ~  uname -a Linux neon 4.4.0-45-generic #66-Ubuntu SMP Wed Oct 19 14:12:37 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux 

Since this might be related to nvidia:

~  dpkg -l | grep nvidia ii nvidia-361 361.42-0ubuntu2 amd64 NVIDIA binary driver - version 361.42 ii nvidia-opencl-icd-361 361.42-0ubuntu2 amd64 NVIDIA OpenCL ICD ii nvidia-prime 0.8.2 amd64 Tools to enable NVIDIA's Prime ii nvidia-settings 361.42-0ubuntu1 amd64 Tool for configuring the NVIDIA graphics driver 

EDIT: Running a few more times, sometimes it also shows me a segfault which may explain:

Error: 111.183169] sddm[980]: segfault at 40 ip 0000000000000040 sp 00007fff1f7f8b78 error 14 in sddm[400000+6f000] 

Output of dmesg: Output of cat /var/log/Xorg.0.log:

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