Bug 391558

Summary: External monitor does not wake up
Product: [Plasma] plasmashell Reporter: Petr Nehez <petr.nehez>
Component: generalAssignee: David Edmundson <kde>
Status: CLOSED NOT A BUG    
Severity: normal CC: kde, nate, plasma-bugs, sebas
Priority: NOR    
Version: 5.12.2   
Target Milestone: 1.0   
Platform: Manjaro   
OS: Linux   
Latest Commit: Version Fixed In:

Description Petr Nehez 2018-03-08 11:19:36 UTC 
My external monitor is not waken up when I move with a mouse or press a key after it has been previously switched off by the system while laptop’s screen is not used at all (OFF) while the monitor is plugged in.

I have to unplug it and then plug it again.

Any idea?

Manjaro KDE, Plasma 5.12.2, Frameworks 5.43, Qt, 5.10.1
Comment 1 Petr Nehez 2018-03-11 07:30:15 UTC 
Does anybody know how to find such problem in logs?

I enabled KScreen logging but there I don't see anything...

In which log can I see something regarding switching off the screen and waking up again?
Comment 2 Petr Nehez 2018-03-12 21:18:58 UTC 
The workaround to wake up the monitor is to start a new terminal (e.g. Ctrl+Alt+F2) and then back to terminal 1 by pressing Ctrl+Alt+F1.

This issue is super annoying...
Comment 4 Nate Graham 2018-03-13 16:32:05 UTC 
Based on the issues outlined in those forum thread, this regression coincided with updating the kernel. Please do some more debugging on the Manjaro forums to isolate the issue. If indeed it's a kernel regression, the issue should be reported on https://bugzilla.kernel.org/.
Comment 5 Petr Nehez 2018-03-14 06:16:47 UTC 
I went back to 4.14 and then downgraded this kernel (even 6 updates back) and the issue is still present.
So it could not be the kernel issue because I am 100% sure this was working fine before the last update of KDE from Manjaro.

Could you suggest me ways how to isolate the issue?
Comment 6 Petr Nehez 2018-03-14 06:33:03 UTC 
Hmm, I upgraded my linux414 packages back to the latest ones and now it seems to be working fine...
I am confused.

I will be watching it and if it starts to work again then... would it be something with the kernel?
Comment 7 Sebastian Kügler 2018-03-14 10:38:22 UTC 
It's highly unlikely that this is a Plasma issue, so I'll close this bugreport (it's not useful to track this here, just muddies up our bug list and makes it harder to manage).

Thanks for the report however!
Comment 8 Petr Nehez 2018-03-14 10:43:16 UTC 
This issue is still present on my laptop though...

Could you at least help me and suggest me a way (ways) how to narrow down the cause? 
Thanks in advance.