I'm using a dv6.
Please give a little more detail than just "dv6". There are about 12-15 "dv6" models out there, so without more specifics, it's hard to tell you what to do.
Here's is tidbit I found here:
"On my wife's system with ATI switchable graphics, the system defaults to always running the discrete card while plugged in and switching to IGP when unplugged. That being said, you can right-click on the desktop and open "Configure ATI PowerXpress" to manually select which adapter is active and you can turn off the auto-switch feature there as well.
"link to where I found this.