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yochaigal

Member

From: Boston

Registered: 2011-02-06

Posts: 202

Completely lose video/display (tty OK) when HDMI is switched out

Infos:

4.0.7-2-ARCH #1 SMP PREEMPT Tue Jun 30 07:50:21 UTC 2015 x86_64 GNU/Linux

GPU: NVIDIA Corporation GM206 [GeForce GTX 960] (rev a1) / Kernel driver in use: nvidia / Driver Version: 352.21 

I've got an HDMI monitor attached; everything works the way it should.
However, when my wife unplugs the HDMI and plugs in her laptop to the HDMI (different cable), and I later return to plug it back into my desktop, it shows only a black screen.
I can switch tty's no problem - a simple restart of my login manager fixes things.
But why does this happen? If I leave my monitor plugged in for a week, it works FINE upon return. It's only when it's been unplugged for a while. Is my card hibernating, or something? And why do tty's work?

Thanks for the help.

Awebb

Member

Registered: 2010-05-06

Posts: 6,688

Re: Completely lose video/display (tty OK) when HDMI is switched out

X does not know what to do with your screen. Please provide details on your DM (login/display manager) and desktop environment.

yochaigal

Member

From: Boston

Registered: 2011-02-06

Posts: 202

Re: Completely lose video/display (tty OK) when HDMI is switched out

Sure. I use XFCE with LightDM; xscreensaver for lock screen.

Awebb

Member

Registered: 2010-05-06

Posts: 6,688

Re: Completely lose video/display (tty OK) when HDMI is switched out

If your screen is attached, a udev event happens. If nothing watches for that event, nothing else happens. You either need to find out how to condigure XFCE or write a udev rule.

yochaigal

Member

From: Boston

Registered: 2011-02-06

Posts: 202

Re: Completely lose video/display (tty OK) when HDMI is switched out

But when I re-attach HDMI, or switch tty (back and forth) shouldn't it force a response from udevadm? What should I look for?
I could change DEs and see if is an XFCE-specific issue.

Awebb

Member

Registered: 2010-05-06

Posts: 6,688

Re: Completely lose video/display (tty OK) when HDMI is switched out

You could test a WM like Openbox with and without LightDM. Both XFCE and the DM could be responsible.