Bug 19743

Summary: mga5.1 Classic iso install of KDE4 fails at login
Product: Mageia Reporter: Len Lawrence <tarazed25>
Component: Release (media or process)Assignee: KDE maintainers <kde>
Status: RESOLVED OLD QA Contact:
Severity: major    
Priority: High CC: marja11, sysadmin-bugs, tmb
Version: 5Keywords: 5.1
Target Milestone: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Source RPM: CVE:
Status comment:
Attachments: journalctl -b output for mga5.1 test iso

Description Len Lawrence 2016-11-09 01:14:59 CET
Description of problem:
On one particular machine (UEFI) the install of KDE4 from the 64bit Classic iso runs smoothly but after reboot the login to KDE4 fails.  As soon as the user credentials are accepted the default KDE background appears but instead of the desktop fading in it disappears and the monitor goes into power-save mode.  It is possible to get back to the login screen but KDE4 remains out of reach but it is possible to login to IceWM without any problem.  A custom install of Mate and KDE4 did not improve matters.  Mate was accessible but still no KDE.  Testing on a UEFI laptop reveals no such problem.  Both machines use higher-end nvidia GTX graphics cards.  The problem machine has had no difficulty in the past with KDE4 on mga5 or Plasma5 on Mageia Cauldron.  No idea what diagnostics might be required.  dmesg is available from one of the installations.

Version-Release number of selected component (if applicable):
Mageia 5.1

How reproducible:
As far as the tests have gone, this occurs on one machine only and it is consistent.  MSI motherboard, nvidia GTX970 graphics.  The monitor is a Dell 4K display connected to the nvidia card on the DisplayPort.  A DVI output is available but I suspect that it connects to the onboard Intel graphics.

Steps to Reproduce:
1. Install Mageia5.1 classic x86_64 on UEFI machine with nvidia graphics.
2. Include KDE4 either in isolation or as part of a custom install.
3. Try to login to KDE4 desktop.
Comment 1 Len Lawrence 2016-11-09 02:08:47 CET
Just tried out my theory that KDE was trying to use the Intel graphics as well.  Connected a 3K monitor to the DVI output, which resulted in two similar Mate desktop displays.  Rebooted and chose KDE at login and saw the KDE desktop established on both screens.  Could not say which was master.

Could this problem be something to do with the way the system configures X?  Two heads and all that.  The user receives no feedback on this at install time.
Whatever is happening does not seem to be reflected in xorg.conf:

Section "Device"
    Identifier "device1"
    VendorName "NVIDIA Corporation"
    BoardName "NVIDIA GeForce 420 series and later"
    Driver "nvidia"
    Option "DPMS"
    Option "DynamicTwinView" "false"
    Option "AddARGBGLXVisuals"
EndSection

Section "Screen"
    Identifier "screen1"
    Device "device1"
    Monitor "monitor1"
EndSection
Comment 2 Len Lawrence 2016-11-09 02:31:57 CET
Tried running drakx11 to ensure that display mode was not forced to DVI but that did not help.  That was a long shot because the real puzzle is what is the difference between the desktops as far as DP and DVI are concerned?  Why or how does KDE require both when Mate is happy to use DP only?  And KDE heretofore worked fine with DP.
Comment 3 Len Lawrence 2016-11-09 02:37:05 CET
Created attachment 8642 [details]
journalctl -b output for mga5.1 test iso
Samuel Verschelde 2016-11-09 10:31:13 CET

Keywords: (none) => 5.1
Priority: Normal => High

Comment 4 Len Lawrence 2016-11-09 12:04:20 CET
Have just performed a GNOME only installation of mga5.1 and logged in without any problem.
Comment 5 Len Lawrence 2016-11-09 12:27:12 CET
Copied the mga5.1 classic iso to another USB key and installed KDE again, KDE only.  Ensured that the latest updates were applied before reboot and tried again.  Just the same, disconnected monitor.
Comment 6 Thomas Backlund 2016-11-09 12:47:10 CET
(In reply to Len Lawrence from comment #0)

> As far as the tests have gone, this occurs on one machine only and it is
> consistent.  MSI motherboard, nvidia GTX970 graphics.  The monitor is a Dell
> 4K display connected to the nvidia card on the DisplayPort.  A DVI output is
> available but I suspect that it connects to the onboard Intel graphics.


If the dvi port is on the graphic card, it's connected to the GTX...
Can you try to confirm (or not) if it's a displayport issue.

CC: (none) => tmb

Comment 7 Len Lawrence 2016-11-09 14:22:27 CET
I checked all this out a year ago.  The DVI output is not on the graphics card.  I had been experimenting with a 3K monitor and found that there was no nvidia graphics with DVI which proved there was no connection to the graphics card.  I was puzzled by the lack of DVI input ports on the monitor and later discovered that DVI does not have the bandwidth to support anything larger than 3K.

Another KDE install on an old nvidia laptop has just booted and passed the login stage OK.

So I think that this shows that this is a Display Port issue, but only for KDE.  And as noted earlier, KDE and Plasma have run without issues on this hardware over the past year or so.  My experiment with the two monitors seems to show that KDE expects to find a DVI connected display before it can continue.  When it finds one, the DP monitor echoes the desktop.

Something has definitely changed in KDE.
Comment 8 Marja Van Waes 2016-11-09 20:40:05 CET
(In reply to Len Lawrence from comment #7)

> 
> Another KDE install on an old nvidia laptop has just booted and passed the
> login stage OK.
> 
> So I think that this shows that this is a Display Port issue, but only for
> KDE.  And as noted earlier, KDE and Plasma have run without issues on this
> hardware over the past year or so.  My experiment with the two monitors
> seems to show that KDE expects to find a DVI connected display before it can
> continue.  When it finds one, the DP monitor echoes the desktop.
> 
> Something has definitely changed in KDE.

Assigning to KDE team, then.

@ tmb, neoclust and all

Please correct me if that's the wrong assignee

CC: (none) => marja11
Assignee: bugsquad => kde

Comment 9 Len Lawrence 2016-11-09 22:18:57 CET
Yes, thanks Marja.  It certainly looks like KDE and an edge case at that.
Comment 10 Len Lawrence 2016-11-15 16:28:31 CET
Apologies.  This bug does not appear to be consistent.  Dumping the ISO to another USB key gives a bootable Live KDE4 using the DP panel.  Sorry for the noise.
First rule; if a USB pendrive gives trouble try another one. :(

Status: NEW => UNCONFIRMED
Ever confirmed: 1 => 0

Comment 11 Len Lawrence 2016-11-15 17:13:48 CET
Scratch that.  Totally confused here.  It was not a Live iso that gave the trouble.  Going to try a copy of the Classic iso again. 
Yes, the problem persists with another drive.  The experiment with the two monitors indicated that there really was a problem.

Status: UNCONFIRMED => NEW
Ever confirmed: 0 => 1

Comment 12 Len Lawrence 2016-11-15 17:44:54 CET
Tried another approach; custom install with GNOME, KDE4 and Mate.  KDE login failed as before, Mate succeeded.
Comment 13 Marja Van Waes 2018-07-12 10:56:58 CEST
Closing as OLD, because this bug cannot exist in newer isos than Mga 5.1, since KDM & KDE were replaced with SDDM & Plasma5

Status: NEW => RESOLVED
Resolution: (none) => OLD