Dell E6510 laptop using Intel Ironlake with agp driver:
vgapci0: <VGA-compatible display> port 0x7110-0x7117 mem 0xf0000000-0xf03fffff,0xe0000000-0xefffffff irq 16 at device 2.0 on pci0
agp0: <Intel Ironlake (M) SVGA controller> on vgapci0
agp0: aperture size is 256M, detected 32764k stolen memory
vgapci0: Boot video device
When docked, my laptop no longer displays using the external monitor. It freezes with a black screen, white cursor in upper leftmost corner. This happens right about the time it should display the normal unix login prompt, right as X11 should launch.
I have to launch in VESA mode for X11 to work properly.
This worked fine in 8.x, 9,x, 10.0.
Disabling the new VT driver by removing kern.vty=vt from /boot/loader.conf in FreeBSD fixes the problem, as per another user who corresponded with me via email.
For PCBSD, removing kern.vty=vt from /boot/loader.conf.pcbsd and remaking the grub boot fixes the problem on my laptop which is using PCBSD 10.1.1 at the moment.