Bug 345846

Summary:	Graphical glitches when trying to switch when changing set of active monitors.
Product:	[Plasma] plasmashell	Reporter:	Diane Trout <diane>
Component:	generic-multiscreen	Assignee:	Aleix Pol <aleixpol>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	kde, mklapetek, plasma-bugs-null
Priority:	NOR	Keywords:	triaged
Version First Reported In:	master
Target Milestone:	1.0
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Photo of laptop screen. Photo of monitor after trying to disable laptop screen output of kscreen-console bug

Description Diane Trout 2015-04-04 05:54:28 UTC

When changing the set of active monitors the display is frequently unusably weird. My typical configuration is a 1366x768 display on a thinkpad x220 table attached to a dell 2001fp 1600x1200.

I have had what should be rendered on both screens squished into the middle third of one display. I have had the display zoomed in being able to show only half of one the logical desktops. 

I'm attaching a mobile phone photo of my laptop screen showing the case where only part of the logical display is available.

(Also I had a lot of trouble even booting into plasma with dual-screen enabled, I had to try several different combinations of OpenGL 3.1, 2.0 using GL or EGL modes, and xrender. and OpenGL 2.0 with EGL was the one that let me log in successfully.

Reproducible: Always

Steps to Reproduce:
1. Carry laptop from home to work
2. Plug in different external monitor, or unplug the VGA cable
3. Play with Fn-F7 (change display settings) hopefully fixing it
or give up and restart the Xserver. (which usually helps)



Expected Results:  
It'd be nice to have the display render correctly.

Using the repository from dci.pangea.org. It is possible that I'm missing some critical package.

I tried to build and install kscreen but that didn't seem to work.

Comment 1 Diane Trout 2015-04-04 05:55:26 UTC

Created attachment 91875 [details]
Photo of laptop screen.

Comment 2 Diane Trout 2015-04-04 06:10:36 UTC

Created attachment 91876 [details]
Photo of monitor after trying to disable laptop screen

My plan was to disable the laptop display, and then renable it to see if I could restart the shell on it. Unfortunately the VGA display ended up glitching out and although I managed to try adjusting the compositor settings a bit I could get a stable display back.

(Until I restarted the X server).

Comment 3 Aleix Pol 2015-04-05 21:21:01 UTC

Marting Graesslin suggested to me to prefer GLX over EGL, maybe that solves these issues for you?

Comment 4 Diane Trout 2015-04-05 22:02:49 UTC

Nope. Switched to OpenGL 2.0 + GLX.

I then tried to make the laptop display the primary display. Then I selected the VGA display and disabled it, after applying, the VGA display went blank, and the laptop display, looked roughly like my first photo.

(Zoomed in on the bottom half of the logical display).

Comment 5 Diane Trout 2015-04-05 22:04:02 UTC

Created attachment 91903 [details]
output of kscreen-console bug

Comment 6 Kai Uwe Broulik 2015-04-05 22:09:50 UTC

I'm seeing similar effects on various devices (one Intel, one AMD, one nvidia), the compositor gets totally confused when screens change. Pressing Alt+Shift+F12 twice fixes it

Comment 7 Diane Trout 2015-04-06 16:10:43 UTC

The Alt-Shift-F12 workaround certainly helps. Thank you.

Comment 8 Martin Klapetek 2016-02-03 20:07:53 UTC

Is this still the case on Plasma >5.5.3 and Qt >5.5.1?

Comment 9 Andrew Crouthamel 2018-09-25 21:38:34 UTC

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days, the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please set the bug status as REPORTED so that the KDE team knows that the bug is ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!

Comment 10 Andrew Crouthamel 2018-10-27 02:52:40 UTC

Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information.

For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!

Comment 11 Diane Trout 2018-10-27 03:29:42 UTC

Oh wow. I forgot about this bug. 

I haven't seen this problem with plasma in a quite a long time.