If I switch from a running X session (on VT7) to another virtual terminal and
then back to the X session the screen is blank.  The system stays running, but
is unresponsive to the keyboard.  The initial switch from the X session works
correctly.

This worked correctly in xorg-6.8, but fails in xorg-7.0 and xorg-7.1.  I have
tried with the latest git vesion of the i810 driver, this also exhibits this
problem.

The machine has an integrated i830m chipset.

This works correctly with the vesa driver.

This stops me being able to suspend my laptop, as the suspend cycle triggers
this problem.

======================
lspci output

00:00.0 Host bridge: Intel Corporation 82830 830 Chipset Host Bridge (rev 04)
00:02.0 VGA compatible controller: Intel Corporation 82830 CGC [Chipset
Graphics Controller] (rev 04)
00:02.1 Display controller: Intel Corporation 82830 CGC [Chipset Graphics
Controller]
00:1d.0 USB Controller: Intel Corporation 82801CA/CAM USB (Hub #1) (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801CA/CAM USB (Hub #2) (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801CA/CAM USB (Hub #3) (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 42)
00:1f.0 ISA bridge: Intel Corporation 82801CAM ISA Bridge (LPC) (rev 02)
00:1f.1 IDE interface: Intel Corporation 82801CAM IDE U100 (rev 02)
00:1f.3 SMBus: Intel Corporation 82801CA/CAM SMBus Controller (rev 02)
00:1f.5 Multimedia audio controller: Intel Corporation 82801CA/CAM AC'97 Audio
Controller (rev 02)
00:1f.6 Modem: Intel Corporation 82801CA/CAM AC'97 Modem Controller (rev 02)
02:02.0 FireWire (IEEE 1394): Texas Instruments TSB43AB22/A IEEE-1394a-2000
Controller (PHY/Link)
02:05.0 CardBus bridge: Ricoh Co Ltd RL5c475 (rev 80)
02:08.0 Ethernet controller: Intel Corporation 82801CAM (ICH3) PRO/100 VE (LOM)
Ethernet Controller (rev 42)
02:0b.0 Network controller: Intersil Corporation Prism 2.5 Wavelan chipset (rev
01)