Disabling console blanking in Debian Linux

I find it particularly annoying that the default settings in a stock base Debian install blanks the monitor after about 30 minutes of inactivity. There are a few servers that I have logged in and running htop 24×7 and it’s inconvenient to have to hit the keyboard every time I need to check in on the system.

I did a quick search on Google, but the only results were hack-ish setterm commands crammed into the rc.local or .bashrc files – sure that would work, but instead of setting it at bootup, then setting it again at login, wouldn’t there be a direct way to change the default behavior of the screen blanking? Go dig in /etc and lets see what we find:

pengc99@janus:~$ sudo grep -r setterm /etc/*
grep: /etc/fonts/conf.d/30-defoma.conf: No such file or directory
/etc/init.d/kbd:    setterm_args=””
/etc/init.d/kbd:        setterm_args=”$setterm_args -blank $BLANK_TIME”
/etc/init.d/kbd:        setterm_args=”$setterm_args -powersave $BLANK_DPMS”
/etc/init.d/kbd:        setterm_args=”$setterm_args -powerdown $POWERDOWN_TIME”
/etc/init.d/kbd:    if [ “$setterm_args” ]; then
/etc/init.d/kbd:        setterm $setterm_args
/etc/rcS.d/S16kbd:    setterm_args=””
/etc/rcS.d/S16kbd:        setterm_args=”$setterm_args -blank $BLANK_TIME”
/etc/rcS.d/S16kbd:        setterm_args=”$setterm_args -powersave $BLANK_DPMS”
/etc/rcS.d/S16kbd:        setterm_args=”$setterm_args -powerdown $POWERDOWN_TIME”
/etc/rcS.d/S16kbd:    if [ “$setterm_args” ]; then
/etc/rcS.d/S16kbd:        setterm $setterm_args
pengc99@janus:~$

Hm, /etc/init.d/kbd looks interesting, so lets take a look in there:

# This is the boot script for the `kbd’ package.
# It loads parameters from /etc/kbd/config and maybe loads
# default font and map.
# (c) 1997 Yann Dirson
< 8< ————- snip ————- >8 >
# screensaver stuff
setterm_args=””
if [ “$BLANK_TIME” ]; then
setterm_args=”$setterm_args -blank $BLANK_TIME”
fi
if [ “$BLANK_DPMS” ]; then
setterm_args=”$setterm_args -powersave $BLANK_DPMS”
fi
if [ “$POWERDOWN_TIME” ]; then
setterm_args=”$setterm_args -powerdown $POWERDOWN_TIME”
fi
if [ “$setterm_args” ]; then
setterm $setterm_args
fi

Hm, it looks like it’s looking for the variable BLANK_TIME and POWERDOWN_TIME in the config file /etc/kbd/config – lets take a look in there:

# screen blanking timeout.  monitor remains on, but the screen is cleared to
# range: 0-60 min (0==never)  kernels I’ve looked at default to 10 minutes.
# (see linux/drivers/char/console.c)
BLANK_TIME=15
< 8< ————- snip ————- >8 >
# Powerdown time.  The console will go to DPMS Off mode POWERDOWN_TIME
# minutes _after_ blanking.  (POWERDOWN_TIME + BLANK_TIME after the last input)
POWERDOWN_TIME=30

Perfect! Change these from their respective values to 0 and it will effectively disable the screen blanking:

BLANK_TIME=0
POWERDOWN_TIME=0

Restart kbd and you’re good to go:

pengc99@janus:~$ sudo /etc/init.d/kbd restart
Setting console screen modes.
Skipping font and keymap setup (handled by console-setup).
pengc99@janus:~$