Can't boot into Ubuntu 15.10 without 'idle

I'm using Ubuntu 15.10(EFI 64bit) on MSI GS40 laptop, which has Intel Skylake processor and Nvidia's dedicated GPU.

I couldn't boot to Ubuntu's installation stage without giving GRUB's boot option 'nomodeset' and 'idle=nomwait'.

I searched throughout the internet, found out that I should install Nvidia's proprietary driver to boot without 'nomodeset', and solved that, but still I can't boot without 'idle=nomwait'.

I finished upgrading whole packages and it still can't. I searched again and I found that this option is related to Intel's C-State policy.

I could't progress further from here. Since I saw 'idle=nomwait' disables Intel's C-State function, I want to boot without this because it's laptop that I use outside. So I really have no choice but this, questioning to you guys. Please help me!

PS. Reinstalling it and going into installation screen or live mode, it says

ACPI : EC: Fail in evaluating the _REG object of EC device. Broken bios is suspected

, but I don't know any clue about it.