Dual head DPMS issue
Using the 9643 driver with a dual head configuration (no composite), the external monitor sometimes does not get DPMS power off.
That is, if I run 'xset dpms force off', about 8 out of ten times it works. About 2 out of 10 times, only the LCD on the laptop powers off, and the external LCD monitor blanks - but the backlight stays on.
This is really annoying when you walk away from the machine, expecting the screensaver to kick in and power off the displays.
Bug report attached.