Bug 361211

Created attachment 98166 [details]
Where are my letters?

Rebooted. Phew. Now I can read everything again. System Info:

Kernel: 4.4.0-16-generic x86_64 (64 bit) Desktop: KDE Plasma 5.5.4
           Distro: Ubuntu 16.04 xenial
Machine:   System: LENOVO (portable) product: 20428 v: Lenovo Yoga 2 11
           Mobo: LENOVO model: VIUU4 v: 31900058WIN Bios: LENOVO v: AACN21WW date: 01/30/2015
CPU:       Dual core Intel Core i3-4012Y (-HT-MCP-) cache: 3072 KB 
           clock speeds: max: 1500 MHz 1: 948 MHz 2: 1500 MHz 3: 602 MHz 4: 605 MHz
Graphics:  Card: Intel Device 0a1e
           Display Server: X.Org 1.18.1 drivers: intel (unloaded: fbdev,vesa) Resolution: 1366x768@60.00hz
           GLX Renderer: Mesa DRI Intel Haswell GLX Version: 3.0 Mesa 11.1.2
Audio:     Card-1 Intel 8 Series HD Audio Controller driver: snd_hda_intel Sound: ALSA v: k4.4.0-16-generic

Happened again after coming out of Sleep Mode. This never used to happen until installing 16.04. Have run 14.10, 15.04 and 15.10 on this laptop.

This is a critical bug.

Created attachment 98210 [details]
Completely gone...

As of 16.04's release, the bug hasn't been as drastic. That is, there appear to have been some improvement since BETA. The problem persists however, usually occurring after suspend. There are occasional hick-ups when Plasma locks up and compositing is restarted.

Also, this is a problem on both my systems -- instability in plasmashell and compositing. Prior to 16.04, neither of my system experienced these instabilities.

Kernel: 4.4.0-21-generic x86_64 (64 bit) Desktop: KDE Plasma 5.5.5
           Distro: Ubuntu 16.04 xenial
Machine:   System: LENOVO (portable) product: 20428 v: Lenovo Yoga 2 11
           Mobo: LENOVO model: VIUU4 v: 31900058WIN Bios: LENOVO v: AACN21WW date: 01/30/2015
CPU:       Dual core Intel Core i3-4012Y (-HT-MCP-) cache: 3072 KB 
           clock speeds: max: 1500 MHz 1: 1500 MHz 2: 1500 MHz 3: 1500 MHz 4: 1500 MHz
Graphics:  Card: Intel Device 0a1e
           Display Server: X.Org 1.18.3 drivers: intel (unloaded: fbdev,vesa) Resolution: 1366x768@60.00hz
           GLX Renderer: Mesa DRI Intel Haswell GLX Version: 3.0 Mesa 11.2.0

Created attachment 98570 [details]
Missing letters in the Firefox Bookmark dropdown menu. 16.04 Final.

That is intel driver bug. Switching to DRI3 fixes it for me.

Look at this thread: https://www.kubuntuforums.net/showthread.php?69984-FIX-for-flickering-flashing-panel-on-Intel-gpu

Thanks, I'll try it, but I don't have a flickering or flashing panel.

(In reply to Nikola Schnelle from comment #7)
> That is intel driver bug. Switching to DRI3 fixes it for me.
> 
> Look at this thread:
> https://www.kubuntuforums.net/showthread.php?69984-FIX-for-flickering-
> flashing-panel-on-Intel-gpu

Okay. Results are in. I followed the advice on the thread. Sdding the 20-intel.conf file actually made the problem much worse.

Well I had "missing letters" problem after wake from suspend in firefox, but since I use DRI3 - never faced the problem again.

Install intel-microcode if you didn't already. Maybe it will help.

Anyway this is not kwin/kde bug.

(In reply to Nikola Schnelle from comment #10)
> Well I had "missing letters" problem after wake from suspend in firefox, but
> since I use DRI3 - never faced the problem again.
> 
> Install intel-microcode if you didn't already. Maybe it will help.
> 
> Anyway this is not kwin/kde bug.

Intel-Microcode?!? I think I'll pass on that. That's like telling me my electric motor needs an oil change.

And as for whether its kwin/kde bug? Maybe you're right. Maybe you're not. As it is, both my systems say it happened after upgrading to Kbuntu 16.04.

Happens to me too after waking up from sleep.

I'm sorry but this is a problem in the rendering of Firefox. We do not develop Firefox. We cannot help you to investigate this. This is a technical issue tracker for KDE software and not a support forum. If you look for support best ask your distribution channels on how to e.g. use the xorg modesettings driver.