How can I use vbetool as a non-root (mmap /dev/zero: Operation not permitted Failed to initialise LRMI (Linux Real-Mode Interface).)

Question

I would like to be able to turn off my screen upon a keypress. I need vbetool to do that (xset dpms force off just blanks it, does not turn it off). However, vbetool needs root priviledges. So I put line my_user_name ALL=NOPASSWD:/usr/sbin/vbetool" into my sudoers file with visudo. However, when I run vbetool dpms off, it says

mmap /dev/zero: Operation not permitted
Failed to initialise LRMI (Linux Real-Mode Interface).

Any ideas how to solve this?

Answer 1

So it turns of the line to put to visudo needs to be as follows:

my_user_name ALL=(ALL) NOPASSWD: /usr/sbin/vbetool

Then sudo vbetool dpms off works.

However, it seems xset dpms force off does the same thing after all. I think it did not work that way a couple of releases back, but now it works.