This is something I've wanted to do for sometime, but haven't really looked into it - so thanks for bringing this up Bob !
I've been running BuZz's great Ubuntu minimal distro for some time on a few Jogglers, and despite what I thought initially they have been rock solid. I'm actually amazed there has not been some problems, even with flaky hubs and flash drives, they still keep on working... So thanks for doing some great work on the distros for the Joggler BuZz !
I wrote a script to control the brightness, which is below :
#!/bin/bash
echo "$1" > /sys/class/backlight/openframe-bl/brightness
Have this as an executable file, say called bright, and invoke with $ sudo ./bright 10
for 10/32 brightness. Range is from 0 to 32, by default in Ubuntu base.
I was quite pleased with this as it is the first UNIX (like) script I've written since doing some work on an IMP and Perkin Elmer in the 80's.
For some time I thought that some of the other pseudo-files in same directory may affect the backlight. These being :
-r--r--r-- 1 root root 4096 Jul 9 01:09 actual_brightness
-rw-r--r-- 1 root root 4096 Jul 9 01:09 bl_power
-rw-r--r-- 1 root root 4096 Jul 9 01:09 brightness
lrwxrwxrwx 1 root root 0 Jul 9 01:09 device -> ../../../openframe-bl
-r--r--r-- 1 root root 4096 Jul 9 01:09 max_brightness
drwxr-xr-x 2 root root 0 Jul 9 01:09 power
lrwxrwxrwx 1 root root 0 Jan 1 2005 subsystem -> ../../../../../class/backlight
-r--r--r-- 1 root root 4096 Jul 9 01:09 type
-rw-r--r-- 1 root root 4096 Jan 1 2005 uevent
it was bl_power I thought.
Anyway, doing the same thing to bl_power as done to brightness, did nothing, as far as I can tell. I'm interested to know what this is for.
Next I thought about putting a physical switch on there some how. Don't know exactly how this could be done, but may work. May also introduce more problems and be a lot more involved than I'm prepared to tinker with.
Like you Bob, I don't want to have an X server running. I'd like to keep things as light as possible.
So, given what has been discussed above, I thought there may be a way to capture the DPMS output from the xset command. First, I had to find out what DPMS was :
https://en.wikipedia.org/wiki/VESA_Disp ... _Signaling
explained a bit.
Then a search for a ubuntu dpms commands turned up the following possibilities :
http://askubuntu.com/questions/62858/tu ... mmand-line
Seems we may have a solution with the vbetool :
http://linux.die.net/man/1/vbetool
http://www.codon.org.uk/~mjg59/vbetool/
It appears that this tool depends on libx86. I'm guessing that it does not require an X server to be running, but just uses some of the code in libx86.
Of course, there's only one way to find out - try it out. Trouble is, if you turn the screen off and it won't turn back on, your left in the dark, so to speak. Wonder, if something could be done from a remote ssh session, then, I presume, that wouldn't be effected, but you could see the result of using vbetool, with whatever parameters used.
HTH
PS
Some other links of interest I came across are :
https://wiki.ubuntu.com/FrameBuffer
https://wiki.ubuntu.com/X/Troubleshooting/BlankScreen
http://systembash.com/content/how-to-tu ... in-ubuntu/
Just wondering if it could be possible to get the backlight off using the framebuffer, fbset command ?
Just looking through the last link, one user states :
Yebo29
sudo vbetool dpms off did the trick for me!