Problem with video output switching
Problems with Intel chipsets
Disabling the internal LCD (e.g. when using an external Monitor) doesn't seem to work reliably.
- i810switch doesn't have any effect. After disabling the LCD it is still on (but the status display of i810switch claims that is is switched off).
- i855crt doesn't seem to allow to change the state of the internal LCD.
- With ibm-acpi,
# echo lcd_disable >/proc/acpi/ibm/videoworks, but
# echo lcd_enable >/proc/acpi/ibm/videodoesn't work - so one can't enable it anymore after disabling it. (the strange thing is that when switching to a console with the LCD display is used for it, so there must be some way to enable it but I can't find out how to control this in X). I've tried this with version 0.8 and version 0.11 of ibm-acpi.
Problems with ATI chipsets
- It is a known issue of xorgs radeon driver that doesn't work.
You can force the radeon driver to enable both CRT and LCD using Option "MonitorLayout" "LVDS,CRT" in the "Device" section of /etc/X11/xorg.conf. The analogous option for fglrx is Option "ForceMonitors" "lvds,crt1"
# radeontool light off and
# radeontool dac off commands will disable the LCD and CRT if they're been enabled before in the X server, but the corresponding
# radeontool light on and
# radeontool dac on will not work if the displays have were not enabled when the X server started. Also note that turing off the CRT using this command will not reduce power consumption, nor allow fglrx to enable power saving modes.
You might try the following: Hit Ctrl+Alt+F1 to switch to a console, hit Fn+F7 to switch video, hit Ctrl+Alt+F7 to switch back to X.