Graphic problem after update to 5.5.3

[bdcomp]

Hi,

I just updated my Kubuntu 15.10 64bit (AMD A8-6500T, Mesa) to Plasma 5.5.3 via the Kubuntu Backports PPA.
Old Xsession file been left while asked about replace to the new version.

After reboot - the screen is full with horizontal lines, although everything seems to work.
But - after killing the X by Ctrl-Alt-Backspace and logging in again, with the same user - everything works.

What I tried, without any result:

1. Clearing ~/.cache directory
2. sudo apt-get install -f
3. sudo dpkg --configure -a
4. Rename of Root/usr/share/sddm/scripts Xsession to Xsession.old and Xsession.dpkg-dist to Xsession

Update: A picture of the lines:
http://pasteboard.co/UtIIj1U.jpg

Any suggestion how to auto login like manually after exiting X?

[bdcomp]

A bug report just filled: https://bugs.launchpad.net/ubuntu/+bug/1535763

Please help me assign and subscribe the right developers.

[Teunis]

I have little experience with AMD video but on nVidia and Intel you can also play with the backend for rendering, the options are, GL 3.1, GL 2.0 and XRender.

[bdcomp]

I solved this (after about 14 hours...) by:
sudo ppa-purge ppa:kubuntu-ppa/backports
Now I am again on Plasma 5.4.3
Just needed to install Muon again:
sudo apt-get install muon

Maybe one day I will try again to update via the Backports PPA and replace the Xsession file.

[Gerii]

Same problem here on AMD R9 290 and stock open source drivers. With XRender it currently seems to work.

[uvarvu]

Do you mean something like this? Then I've noticed it too. The problem goes away when switching to XRender.

[bdcomp]

Do you mean something like this? Then I've noticed it too. The problem goes away when switching to XRender.

No.
Take a look at the link in message 1.

[uvarvu]

The problem came back after switching from OpenGL 3.1 to XRender but it only seems to affect the task bar for me (not sure if my environment being a VM is relevant). I rolled this back and tried changing the OpenGL interface to EGL instead, things are much better now!

[Gerii]

Even with XRender the screen sometimes goes completely black (usually a few minutes after logging in). Only killing my X Server helps in those cases.

[Gerii]

This is definitely related to sddm, now that I've switched to mdm this hasn't happened anymore.