You can turn on/off the dedicated graphics card via OpenSource drivers (acpi_call, vgaswitcheroo, come to mind). However, there is no way to direct the display to the card. This card comes with Pavilion dv6.
The proprietary drivers fail to boot Xorg and the Open source drivers return:
vga_switcheroo: client 0 refused switch
This message indicates that the card can not be switched during X. Restarting Xorg results in the laptop hanging. Now that fixed mode is available as indicated below, you can switch on ATI card permanently (for the session) in Windows.