Kubuntu 18.04 gives black screen when SDDM starts (no login)

Graphics / Linux Linux
1

After upgrading from 17.10 to 18.04 I could only have DE with the Intel gpu. Many options tested in grub like the typical nomodeset.

[url]https://pastebin.com/DuZfv57Z[/url] grub config
[url]https://pastebin.com/26L9sfCE[/url] xorg config

I need a fix soon to could work with the Nvidia GPU and Cuda
nvidia-bug-report.log.gz (108 KB)

2

Please run nvidia-bug-report.sh as root and attach the resulting .gz file to your post. Hovering the mouse over an existing post will reveal a paperclip icon.

3

Done, thanks for your help.

4

It’s an Optimus system with hybrid graphics. Don’t use the .run installer, uninstall it. Use only the drivers from ubuntus graphics ppa. Have the package nvidia-prime installed, remove the ‘nomodeset’ parameter, run sudo prime-select nvidia and reboot.

5

I am already using the official package provided by Ubuntu repositories (nvidia-driver-390 metapackage that installs all necessary). Nvidia prime it’s installed (I am using Kubuntu in this laptop with nvidia-prime for 2 years). The 'nomodeset" parameter its removed from grub config (I already read your post about blank screen problems). But when I reboot with Nvidia I always get a blank screen when SDDM it’s launched.

6

Ok, but your xorg.conf is still one generated by nvidia-xsetup which doesn’t fit. It should have been overwritten by gpumanager. Please check if the package ubuntu-drivers-common is installed.
Otherwise, you can use the xorg.conf from ths post:
https://devtalk.nvidia.com/default/topic/1022670/linux/official-driver-384-59-with-geforce-1050m-doesn-t-work-on-opensuse-tumbleweed-kde/post/5203910/#5203910
Then, the file /usr/share/sddm/scripts/Xsetup has to contain

xrandr --setprovideroutputsource modesetting NVIDIA-0
xrandr --auto
7

ubuntu-drivers-common already installed

#!/bin/sh
# Xsetup - run as root before the login dialog appears

if [ -e /sbin/prime-offload ]; then
    echo running NVIDIA Prime setup /sbin/prime-offload
    /sbin/prime-offload
fi

xrandr --setprovideroutputsource modesetting NVIDIA-0
xrandr --auto

It’s correct the Xsetup like that?

8

Yes, the file /sbin/prime-offload should contain the same commands.

9

If I understand well that code, it’s not enough to put that two commands in the prime-offload? (I mean that its not necessary in Xsetup if we write it in prime-offload)

10

Misunderstanding. The file prime-offload should already contain that before.

11

Then if now my Xsetup it’s ok, I only had to change the xorg.conf that I generated with nvidia-xconfig for the one you said. But it worries me that it have references to other monitors with different resolutions than mine. Could I proceed anyway?

Section "ServerLayout"
    Identifier     "layout"
    Screen      0  "nvidia" 0 0
    Inactive       "intel"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    Modeline "1280x720_60.00"  74.48  1280 1336 1472 1664  720 721 724 746  -HSync +Vsync
EndSection

Section "Device"
    Identifier     "intel"
    Driver         "modesetting"
    Option         "AccelMethod" "none"
    BusID          "PCI:0:2:0"
EndSection

Section "Device"
    Identifier     "nvidia"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BusID          "PCI:1:0:0"
    Option         "AllowEmptyInitialConfiguration"
EndSection

Section "Screen"
    Identifier     "nvidia"
    Device         "nvidia"
    Monitor        "Monitor0"
    SubSection     "Display"
        Virtual     1920 1080
    EndSubSection
EndSection
12

I was thinking that maybe I had an automatic copy of my xorg.conf when upgraded (the one that worked well before), and it was there, so I did a test with that one and worked!. So I will write down here the change and configuration that made work again my Nvidia in a laptop with Optimus.

Added lines 9 and 10 to usr/share/sddm/scripts/Xsetup:

#!/bin/sh
# Xsetup - run as root before the login dialog appears

if [ -e /sbin/prime-offload ]; then
    echo running NVIDIA Prime setup /sbin/prime-offload
    /sbin/prime-offload
fi

xrandr --setprovideroutputsource modesetting NVIDIA-0
xrandr --auto

My working xorg.conf:

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "nvidia"
    Inactive "intel"
EndSection

Section "Device"
    Identifier "intel"
    Driver "modesetting"
    BusID "PCI:0@0:2:0"
    Option "AccelMethod" "None"
EndSection

Section "Screen"
    Identifier "intel"
    Device "intel"
EndSection

Section "Device"
    Identifier "nvidia"
    Driver "nvidia"
    BusID "PCI:1@0:0:0"
    Option "ConstrainCursor" "off"
EndSection

Section "Screen"
    Identifier "nvidia"
    Device "nvidia"
    Option "AllowEmptyInitialConfiguration" "on"
    Option "IgnoreDisplayDevices" "CRT"
EndSection

Thank you very much generix, now I could properly work again in Blender and my CAD software.