I’m using CentOS on a laptop that part of the time is connected to a docking station with two monitor connected to it. When the laptop lid is docked, its lid is closed, as the system is placed in a position where it’s not convenient to keep it open, let alone look at the screen.
Now in the past, with CentOS 5 (on a different laptop, but same physical config) and 6, the screen has automatically been switched off in this configuration – it’s been as if it was no longer there after I docked the machine, which is of course exactly what I want. After I recently switched to CentOS 7, however, I no longer get this behaviour. Even thought I can’t see the screen, it’s obvious that it’s on, or at least the system thinks so – it appears in display config, and xrandr mentions it as “connected”.
Any idea what’s going on? Shouldn’t the screen just switch of automatically? What part of the system is supposed to handle this anyway? And what’s the best way around my problem? I’ve already disabled the screen in Display preferences, of course, but it seems like the situation should ideally be handled at a more global level, and also,
*my* display config obviously has no effect on the login manager. Which means I can’t really log in while the machine is locked, as the monitor is then still on, and guess where the login window appears…