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Dual Monitors & Power Loss on Main Monitor - Printable Version

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Dual Monitors & Power Loss on Main Monitor - JmaCWQ - 06-12-2016

I have an MSI L1350D Notebook that has a 10" screen of 1024x600 resolution & it also has an external monitor port from which I run a Phillips 17" 1280x1024 monitor.
The Phillips 17" is used as the main monitor with the notebook's monitor disabled.
Just had a thunderstorm roll through & was half way into installing an OS in Virtualbox & the power went out.
As the main monitor was on external power it also went out, the notebook runs via it's own battery when mains power goes out so it was still powered on ok but had no display working so I couldn't do anything with it.

Is there a way to access/start a disabled monitor if the main monitor loses power?
Function keys don't seem to work unfortunately, which would be great if they did as they're supposed to toggle between running either external monitor or built in monitor or both, but regardless if they're both set to being used or not in Display settings nothing happens when the Fn switch combination is pressed.

I can run them both at once but it causes issues with screen tearing, video playback etc. & I was wondering if anyone knows a way to start a disabled monitor if the main monitor goes down for some reason.
Once a monitor has been disabled the only way to enable it again that I know of is using another monitor to view things & change the settings again, ok if there's power to both but useless if one is disabled & the other has no power.
Booting into a live distro both monitors will work provided they have power & the original notebook monitor works regardless as it's on battery, but to get there from the above scenario it leaves the problem of improper shutdown & any unsaved work before the power down will most likely be lost.

Re: Dual Monitors & Power Loss on Main Monitor - JmaCWQ - 09-27-2016

Forgot about this until the power went out again earlier & l lost more work  Sad

The solution is simple, create an application shortcut in the keyboard settings to run the xrandr command that enables the notebook's monitor.

What I found was when using monitors of 2 different resolutions, if the larger external display is used as the primary & xrandr is used to start the disabled smaller one, the smaller one will try to display at the same resolution as the primary/larger one, in my case I had 1280x1024 as the primary & the smaller one is 1024x600.
When the smaller one was started I found the panel was off the screen, couldn't be used etc.
I know there are parameters for resolution etc. that can be used in the xrandr commands but I couldn't make them work, instead I found that disabling the signal being sent to the larger monitor made the smaller one display correctly.

To find what displays are connected on the system open Terminal, type in xrandr and hit Enter.
You should get something appearing that looks similar to this:

Code:
home@debian:~$ xrandr
Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 4096 x 4096
LVDS1 connected (normal left inverted right x axis y axis)
   1024x600      60.00 +
   800x600       60.32    56.25 
   640x480       59.94 
VGA1 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 337mm x 270mm
   1280x1024     60.02*+  75.02 
   1280x960      60.00 
   1152x864      75.00 
   1024x768      75.08    70.07    60.00 
   832x624       74.55 
   800x600       72.19    75.00    60.32    56.25 
   640x480       75.00    72.81    66.67    60.00 
   720x400       70.08

On my setup LVDS1 is the smaller notebook monitor, while VGA1 is the larger external monitor.

The command for the application shortcut to enable the notebook's monitor using xrandr is:

Code:
xrandr --output LVDS1 --auto

The command for the application shortcut to disable the signal to the larger external monitor is:

Code:
xrandr --output VGA1 --off

To run both of those in one action from the Terminal it's:

Code:
xrandr --output LVDS1 --auto && xrandr --output VGA1 --off

Unfortunately that single command doesn't work with the application shortcuts  (if it does I couldn't figure out how), 2 seperate entries have to be created.
One using xrandr --output LVDS1 --auto to enable the notebook's monitor and the 2nd, xrandr --output VGA1 --off to disable the signal to the external monitor.

8)




Re: Dual Monitors & Power Loss on Main Monitor - Valtam - 09-27-2016

Thank you for sharing this JmaCWQ.

Re: Dual Monitors & Power Loss on Main Monitor - JmaCWQ - 09-28-2016

You are welcome Jerry  8)
Sure good to know work can be saved & shutdown performed correctly next time it happens.

Re: Dual Monitors & Power Loss on Main Monitor - Valtam - 09-28-2016

Excellent Smile