On Wed, Oct 20, 2010 at 1:38 PM, Pasi Kärkkäinen <pasik@xxxxxx> wrote: > On Sun, Oct 17, 2010 at 03:25:09PM -0400, Alex Deucher wrote: >> On Sun, Oct 17, 2010 at 9:07 AM, Pasi Kärkkäinen <pasik@xxxxxx> wrote: >> > Hello, >> > >> > While I was discussing the laptop lid/dock issues with Fedora >> > people this issue was brought up. >> > >> > How do you determine if a display is actually powered on or not? >> > >> > Scenario: >> > - Laptop in a docking station, lid open, so internal LVDS enabled. >> > - External DVI display connected, but powered off. >> > >> > So in this case the external display shouldn't be used, since it's off. >> > >> > What happens is this: >> > >> > # cat /sys/class/drm/card0-DVI-D-1/status >> > connected >> > >> > # cat /sys/class/drm/card0-DVI-D-1/enabled >> > enabled >> > >> > # cat /sys/class/drm/card0-DVI-D-1/modes >> > 1920x1080 >> > 1600x1200 >> > 1680x1050 >> > 1280x1024 >> > 1440x900 >> > 1280x960 >> > 1280x800 >> > 1024x768 >> > 800x600 >> > 800x600 >> > 640x480 >> > >> > So it *looks* like it's enabled and active, but actually it's powered off. >> > Is there a method to determine the actual state? >> > >> >> Unfortunately not. Monitors are designed to keep the EDID powered up >> even if the monitor is powered off so that graphics chips can detect >> that something is attached. There's no way to know whether the >> monitor is on of off however. >> > > Ok. Understood. > > And there are no other protocols that would reply only when the monitor is actually on? :) Nope. Alex > > -- Pasi > >> Alex >> >> > That is pretty important information for the daemon/tool/script implementing >> > the "policy" of which outputs to enable/disable.. >> > >> > Thanks! >> > >> > -- Pasi >> > >> > _______________________________________________ >> > dri-devel mailing list >> > dri-devel@xxxxxxxxxxxxxxxxxxxxx >> > http://lists.freedesktop.org/mailman/listinfo/dri-devel >> > >> _______________________________________________ >> dri-devel mailing list >> dri-devel@xxxxxxxxxxxxxxxxxxxxx >> http://lists.freedesktop.org/mailman/listinfo/dri-devel > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
