I get the same problem on my HP Compaq nx8420 laptop with Radeon Mobility X1600 and open source ati driver,
The screen backlight is off on resume, so I ctrl-alt-f7 to return to desktop and then killall vbetool to stop 100% cpu usage, which returns me to a blank screen, so I ctrl-alt-f7 and I'm back to normal.
Jaunty Jackalope fresh install up to date as of May 1, 2009.
I get the same problem on my HP Compaq nx8420 laptop with Radeon Mobility X1600 and open source ati driver,
The screen backlight is off on resume, so I ctrl-alt-f7 to return to desktop and then killall vbetool to stop 100% cpu usage, which returns me to a blank screen, so I ctrl-alt-f7 and I'm back to normal.
Jaunty Jackalope fresh install up to date as of May 1, 2009.