Laptop fans never stop spinning once started

I have Dell Inspiron 7559 with i7 6700HQ cpu.
Once the fans are started to spin because of CPU is heated up, fans runs constantly even when the system is idle and cooled down (CPU/GPU to +30~35C) I've tried kernels up to 4.6 final with the same result. I believe this is kernel/(driver?) issue, since on the very same laptop on windows, fans are switching off on idle. Actually on the same temperatures on Windows the laptop is completely quiet.
On Xubuntu I left laptop idle couple of hours and fans never stopped, but the CPU was cool enough to stop them.
If I put the laptop to sleep which stops the fans and then resume it immediately, the fans are remaining stopped until next CPU heating up...
I've mentioned my problem here with HW info
https://answers.launchpad.net/ubuntu-certification/+question/293705