I have a monitor connect to a Raspberry Pi via HDMI. When I turn on the Raspberry Pi with the monitor off, and then turn the monitor on, I don't get any output. The HDMI only comes on if the monitor was on when the Pi was booting. Is there a way to turn the display on after booting up? E.g. is I log in via ssh. I'm running Raspbian.
Try issuing the following ssh command (assumimg that RPI is the host name of the Raspberry Pi connected via HDMI):
ssh pi@RPI DISPLAY=:0 xset dpms force on
Valid options to the 'xset dpms force' command are 'standby', 'suspend', 'off', or 'on'. See the xset manpage for more details.
I hope that helps.