Hi,
is there a way to check programmatically (via ioctl(), etc.) or by reading a file in /sys, /proc or /dev) whether the screen has been blanked by the Linux console screensaver?
Thanks and best regards,
Günter
A:
I haven't done any desktop development in ages, but memory tells me that most linux screensavers were being executed by xscreensaver - maybe checking whether the process is running, or going through its source-code to see for any system-state being set, or asking on the project maillist would yield some results. Of course KDE and Gnome might have separate screensaver implementations by now - there is very little uniformity when it comes to linux GUIs, unfortunately...
vstoyanov
2010-10-01 16:37:21
+1
A:
You can parse the output of xset q with DISPLAY set, but it's not pretty.
$ xset q
Keyboard Control:
auto repeat: on key click percent: 0 LED mask: 00000000
XKB indicators:
00: Caps Lock: off 01: Num Lock: off 02: Scroll Lock: off
03: Compose: off 04: Kana: off 05: Sleep: off
06: Suspend: off 07: Mute: off 08: Misc: off
09: Mail: off 10: Charging: off 11: Shift Lock: off
12: Group 2: off 13: Mouse Keys: off
auto repeat delay: 250 repeat rate: 30
auto repeating keys: 00ffffffdffffbbf
fadfffefffedffff
9fffffffffffffff
fff7ffffffffffff
bell percent: 50 bell pitch: 400 bell duration: 100
Pointer Control:
acceleration: 20/10 threshold: 4
Screen Saver:
prefer blanking: yes allow exposures: yes
timeout: 0 cycle: 600
Colors:
default colormap: 0x20 BlackPixel: 0 WhitePixel: 16777215
Font Path:
/usr/share/fonts/misc,/usr/share/fonts/100dpi:unscaled,/usr/share/fonts/75dpi:unscaled,/usr/share/fonts/TTF,/usr/share/fonts/Type1,/usr/share/fonts/misc/,/usr/share/fonts/TTF/,/usr/share/fonts/Type1/,/usr/share/fonts/100dpi/,/usr/share/fonts/75dpi/,built-ins
DPMS (Energy Star):
Standby: 1200 Suspend: 1800 Off: 0
DPMS is Enabled
Monitor is On
Font cache:
Server does not have the FontCache Extension
Daenyth
2010-10-01 16:39:45
Thanks, this does the trick. Not the most elegant solution, but checking the output for "Monitor is on|off" works.
obiltschnig
2010-10-02 04:54:37
This is fine, but it relies on an X server being available. If you just have a console (which is rare these days, admittedly), it won't work.
Gabe
2010-10-02 05:16:35
In my case it's fine. I'm running a fullscreen Gtk-WebKit browser which leaks memory like a sieve, so after the screen has been turned off for a while I can safely kill and restart the browser ;-) Of course it would be nice not to have those leaks in the first place...
obiltschnig
2010-10-02 09:53:20
@obiltschnig: Look into valgrind.
Daenyth
2010-10-02 14:33:21
I would but I don't have the time and resources to fix WebKitGTK+... For now, dirty tricks will have to do.
obiltschnig
2010-10-04 06:36:25
+2
A:
Okay, checked the xset source code. The relevant code parts are
#include <X11/extensions/dpms.h>
...
Display* dpy = XOpenDisplay(NULL);
...
int dummy;
CARD16 standby, suspend, off;
BOOL onoff;
CARD16 state;
printf("DPMS (Energy Star):\n");
if (DPMSQueryExtension(dpy, &dummy, &dummy))
{
if (DPMSCapable(dpy))
{
DPMSGetTimeouts(dpy, &standby, &suspend, &off);
printf (" Standby: %d Suspend: %d Off: %d\n",
standby, suspend, off);
DPMSInfo(dpy, &state, &onoff);
if (onoff)
{
printf(" DPMS is Enabled\n");
switch (state)
{
case DPMSModeOn:
printf(" Monitor is On\n");
break;
case DPMSModeStandby:
printf(" Monitor is in Standby\n");
break;
case DPMSModeSuspend:
printf(" Monitor is in Suspend\n");
break;
case DPMSModeOff:
printf(" Monitor is Off\n");
break;
default:
printf(" Unrecognized response from server\n");
}
}
}
}
Just in case anyone else needs this ;-)
obiltschnig
2010-10-02 05:05:30