Change Linux console screen blanking behavior

Question

How do I change the screen blanking behavior on Linux virtual terminals?

For example, if I switch to a VT from X, login, and leave the system alone for 5 minutes or so, the screen will blank like a screensaver. It comes back with any keypress, like a screensaver.

Mostly I just want to change the timeout, but I'm also interested in other settings.

If it helps, one of my systems is running Ubuntu 10.04 with the stock graphics drivers. fbset shows the console using the radeondrmfb framebuffer device.

Answer 1

setterm from @whitequark's answer is a reasonable userspace tool, but it's not the whole story.

The default console blanking behavior is baked into the kernel at compile time. It is configurable at boot time with the paramater consoleblank=, or in userspace with setterm. From the kernel documentation (kernel-parameters.txt):

consoleblank=  [KNL] The console blank (screen saver) timeout in
               seconds. Defaults to 10*60 = 10mins. A value of 0
               disables the blank timer.

Here are the options, their defaults on my Ubuntu system, and their spheres of influence:

• setterm -blank [0-60]; always reports 0 when queried; effective when run on a real VT; affects all real TTYs; not effective when run in screen sessions on a VT.
• setterm -powerdown [0-60]; always reports "3]" (??); doesn't seem to have any effect. Ubuntu kernels don't enable APM_DISPLAY_BLANK, and this could be related.
• consoleblank=N; defaults to 600 (10 minutes); affects all real VTs; affects screen sessions in a VT; no way to set while running.

So my options for changing the default is one of the following:

1. Add setterm -blank X (X in minutes, 0 to disable) to a shell init file like .bashrc.
2. Add setterm -blank X to /etc/rc.local.
3. Add consoleblank=Y (Y in seconds, 0 to disable) to the kernel commandline by adding it to the parameter lists in /etc/default/grub, either GRUB_CMDLINE_LINUX or GRUB_CMDLINE_LINUX_DEFAULT. (Don't forget to update-grub.)

Answer 2

Try setterm -blank $minutes (or pass 0 to disable); -powersave option may also be related. setterm has a plenty of other useful options, too.

If you want to set these attributes on system startup, consider writing an initscript. This is just a script placed in /etc/init.d directory. Let it be called setterm:

#!/bin/sh
[ "$1" == "start" ] || exit 0 # only initialize everything when called as /etc/init.d/setterm start
for term in /dev/tty[0-9]*; do # select all ttyNN, but skip ttyS*
    setterm -blank 0 >$term <$term
    setterm -powersave off >$term <$term
done

Then make it executable:

# chmod +x /etc/init.d/setterm

And finally, create the /etc/rcX.d symlinks (the Debian way):

# update-rc.d setterm defaults

(If you'll get tired of that behavior, do # update-rc.d -f setterm remove. Note that -f must be the first argument).