I have been running X desktop on Raspbian to a iiama TV (HDMI to DVI input).
Most of the time all is well & I can switch off the TV for a time, and back on, waking the screensaver via keyboard.
However, sometimes the screen stays blank: cycling the inputs doesn't help, the Pi is still working (can login on another tty) but don't know how to resurrect X display.
Any suggestions other than killing process & restarting? Don't want to lose
real-time displayed data.