Ubuntu 16.04: problem with multiscreens, is there a workaround?
My configuration is the following:
- computer is a Dell M3800 (a beefy laptop); its internal display is 15 inch, 1920x1080 resolution;
- there is also an external display, which is a 24 inch display, same resolution, connected via HDMI.
There is something really strange since the upgrade, and I'm not sure why that is...
The configuration of the displays is so that the laptop is on the left (which it is, physically) and the large screen on the right. I have windows on both screens.
When I leave the computer alone and screens enter "power saving", if I wake the screens up, all windows are "back" to the laptop screen...
Since the initial question, I have noticed that in fact this has nothing to do with my locking the screen at all; it is systematic as long as the screens enter power saving mode (note: the screens, not the computer).
For this I have tried another configuration: only activate the Asus monitor via HDMI and deactivate the laptop's internal display... On wake up, the laptop screen highlights briefly before X "remembers" that "uh no, the guy wants the external display only" and switches back to the wanted configuration again.
Also, this laptop has an nVidia chipset, and it doesn't matter whether I use the nouveau driver or nVidia proprietary driver: the effects are the same.
I have opened a bug (link), but in the meanwhile, is there a workaround for this apart from, in settings, never let the screens "fall asleep", which is a waste?
I have the same laptop but with a 4k screen and i don't have this issue although my external screen is connected via displayport/thunderbolt.
I found that the HDMI socket was not as reliable for external screens and would struggle with my 4k external screen, that said your resolutions shouldn't be a problem.
There might be some issues with HDMI-CEC which can be used to control screens via HDMI - http://hdmicec.blogspot.co.uk/2012/05/how-to-find-out-if-your-device-is-hdmi.html
I found it was much more reliable on my setup if i used the graphics drivers ppa https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa
I use nvidia-367 and it seems to be much faster at initialising screens, previous versions often timed out getting 4k sync so would take ages to start and give me errors.