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? :) -- 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
