Graphic card switch bug

Hi,

I'm using Dell 5558 with intel core i5 5200U CPU and nvidia 920M GPU. The problem is when i quit a game that uses dedicated video card (in my case Portal) cooling fan doesn't stop untill the laptop is shot down or  nvidia control panel, experience or some diagnostic/monitoring program (e.g. GPU-Z) is not opened. It isn't a unique problem I found two posts regarding this:

http://en.community.dell.com/support-forums/laptop/f/3519/t/19658812

http://en.community.dell.com/owners-club/alienware/f/3746/t/19603774

These are exactly the same bugs as i have. I'm using the latest BIOS version (A09) and nvidia driver.

I would like to ask is there any fix or solution about this issue.

Thanks,

Gergő