I have seen some questions on turning HDMI screens off but my question concerns GPIO attached touchscreens. When I run sudo halt -h
on my b+, the OS(hacked version of Raspbian to work with touchscreen) shuts down.
However, the back-light stays on giving me a bright white screen. I assume this is because the 5v pin is still supplying 5 volts to the screen.
To fix this I know I could wire a switch in series with the power supply or just pull out the cord but I would like to avoid the extra step. Is there a software solution for this to turn the screen off?
/sys/
(particularly/sys/devices
) and see if there's anything there; LED monitor drivers sometimes have a/sys/class/backlight
control./sys
it would just be a matter of writing a value to the appropriate node; I canecho N > /sys/class/backlight/acpi_video0/brightness
where N is an integer between 0 and the value in/sys/class/backlight/acpi_video0/max_brightness
. Those aren't real files, they're conduits to/from the kernel. Some of them are read-only, some of them can be modified by writing to them.