Re: Monitor switched off after resume from hibernation
On Fri 06 Jan 2017 at 22:00:45 (+0100), solitone wrote:
> On Thursday, January 5, 2017 7:52:20 PM CET David Wright wrote:
> > Do you perhaps need
> >
> > xset -display <something> dpms force on
> >
> > in the systemd script?
>
> no, I've also tried with the -display option, but I don't get anything, with
> that command in either the pre block or the post block.
>
> BTW, on my system the -display option doesn't seem to be needed, because if I
> do:
>
> $ sleep 1; xset dpms force off; sleep 2; xset dpms force on
>
> in a terminal, the screen switches off and on as expected.
Yes, but in your terminal, you'll probably find that
$ echo $DISPLAY
will give you :0 (locally) or localhost:10.0 (if you ssh into
another computer). So your terminal's xset command will be
happy without -display as it's got $DISPLAY instead.
$ xset c 99 # good
$ xset c 1 # good
$ xset -display :1 c 99 # bad
xset: unable to open display ":1"
$ DISPLAY="" xset c 99 # bad
xset: unable to open display ""
$ DISPLAY="" xset -display :0 c 99 # good
$
I'm assuming that a systemd command that suddenly pops up from nowhere
will not have a suitable value for $DISPLAY.
If I put
* * * * * /usr/bin/xeyes
into my crontab, I get an error message mailed to me
every minute as above. If I replace it with
* * * * * DISPLAY=":0" /usr/bin/xeyes
I get a new pair of eyes popping up on the screen every minute.
Cheers,
David.
Reply to: