tjaalton and bryceh suggested bisecting using the packages built from mainline rather than building from scratch.
Using <http://kernel.ubuntu.com/~kernel-ppa/mainline/>
v2.6.39-rc1-natty when the external monitor is plugged in will _only_ use the external monitor; the monitors control panel apparently cannot even detect the internal monitor. If I unplug the displayport cable the internal screen is stuck black.
v2.6.39-rc4-natty seems to work correctly.
rc2 apparently failed to build.
tjaalton and bryceh suggested bisecting using the packages built from mainline rather than building from scratch.
Using <http:// kernel. ubuntu. com/~kernel- ppa/mainline/>
v2.6.39-rc1-natty when the external monitor is plugged in will _only_ use the external monitor; the monitors control panel apparently cannot even detect the internal monitor. If I unplug the displayport cable the internal screen is stuck black.
v2.6.39-rc4-natty seems to work correctly.
rc2 apparently failed to build.