On 12/10/2014 11:37 AM, Ron Hardin wrote:
As some of our older XP Pro (Dell) laptops age, they've started to think that
there's activity and keep the display on, when it's set to turn off in ten
minutes of inactivity.

There's processess running (they're used as cpu servers) but no keyboard
activity.

Is there a known reason for this and can it be fixed?

Turning the monitor off with

#include windows.h
main() {
sleep(1);
SendMessage(HWND_BROADCAST, WM_SYSCOMMAND, SC_MONITORPOWER, (LPARAM) 2);
exit(0);
}

turns it off but only for a short time (time varies with machine).

Most of our machines act normally (so far).

(One "fix" is setting the machine to "do nothing" when the lid is closed, and not
ask for a password on return from sleep, and then closing the lid enough to turn
off the display, but you don't get quick access that way. But fixing the problem
would be nicer.)


The problem is not unique to Dell - it happens with a couple of
my home-grown desktops. Both run WinXP SP3.

I've found that setting the monitor turn-off period to 5 minutes
or less mitigates the problem, but it does not cure it.

When I observe a monitor that stayed on, after 5 minutes of
inactivity, I reset the monitor turn-off period (to the usual
5 minutes); then it will be OK for another period of days --
sometimes a long as a month.

The problem is a minor annoyance, but modern LCD monitors do
not have the screen-burn problem of old CRTs.
--
Cheers, Bob