Bug 356839

Summary:	plasma 5 doesn't start on very old PCs who have a graphic card who supports only openGL 1.3
Product:	[Plasma] plasmashell	Reporter:	Potomac <mister.freeman>
Component:	general	Assignee:	David Edmundson <kde>
Status:	RESOLVED INTENTIONAL
Severity:	grave	CC:	bshah, opensuse.lietuviu.kalba, plasma-bugs-null
Priority:	NOR
Version First Reported In:	5.5.1
Target Milestone:	1.0
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Potomac 2015-12-17 15:54:35 UTC

I tried to install plasma 5.5.1 on a very old PC ( pentium 2.4 Ghz, graphic card radeon 9000 AGP ) with archlinux 32 bits,

the driver for the graphic card : radeon open source driver,

and I get only a black screen at startup, the PC seems frozen, I tried with startx : black screen and no cursor mouse, the PC is frozen,

sddm seems to have the same problem : a black screen, I am unable to see the login/password page,

what are the minimal hardware requirements in order to use plasma 5 ?

it seems that plasma 5 can not boot if the graphic card supports only openGL 1.3, there is someting in plasma 5 who prevents old graphic cards to work,

if I use kdm and kde 4.x there is no problem with this old PC,

and there is also no problem with lxqt ( who uses Qt5 libs )

Reproducible: Always

Steps to Reproduce:
1. install plasma 5.5.1 on a very old PC ( from 2003 for example, with a graphic card who supports only openGL 1.3 )
2. try to boot plasma 5.5.1 ( startx or sddm )
3. you will get a black screen at startup, with keyboard frozen and no mouse cursor

Actual Results:  
black screen, keyboard frozen and no cursor mouse

Expected Results:  
plasma 5.5.1 should start on old PCs, even if the graphic card is very old and supports only openGl 1.3

Comment 1 opensuse.lietuviu.kalba 2015-12-17 20:18:26 UTC

This is known:
KDE Plasma 5 needs OpenGL 2.

Try use Software accelerator instead of hardware:
echo 'QT_XCB_FORCE_SOFTWARE_OPENGL=1' > ~/.bashrc
echo 'LIBGL_ALWAYS_SOFTWARE="true"' > ~/.bashrc

This will add two line in /home/[username]/.bashrc :
QT_XCB_FORCE_SOFTWARE_OPENGL=1
LIBGL_ALWAYS_SOFTWARE="true"

Or you can create /etc/xdg/plasma-workspace/env/plasma-Qt5-OpenGL2.sh file with content (and make this file executable):

#!/bin/sh
OPENGL_VERSION=`LANG=C glxinfo | grep '^OpenGL version string: ' | head -n 1 | sed -e 's/^OpenGL version string: \([0-9]\).*$/\1/g'`
if [ "$OPENGL_VERSION" -lt 2 ]; then
  QT_XCB_FORCE_SOFTWARE_OPENGL=1
  export QT_XCB_FORCE_SOFTWARE_OPENGL
fi

Comment 2 David Edmundson 2015-12-20 20:48:33 UTC

Comment 1 is correct.

If the suggested env var does fix your issue, please file a bug with Qt.