[virtio] Xubuntu 20.04 - Blank screen after login

Bug #1868780 reported by Mike Glover on 2020-03-24
This bug affects 2 people
Affects Status Importance Assigned to Milestone
lightdm (Ubuntu)

Bug Description

Both on Xubuntu 20.04 23rd March and 24th March daily build.
Using Martin Wimpress QuickEMU setup.
Installation part of xubuntu is working fine.
But after install and reboot, you get the login box. I type in the password for the user and then just get a black screen and mouse cursor, no other error boxes or gui.
Have tested my QuickEMU setup on ubuntu-mate and do not see this issue, only on Xubuntu daily builds do I see this issue.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.4.0-18.22-generic 5.4.24
Uname: Linux 5.4.0-18-generic x86_64
ApportVersion: 2.20.11-0ubuntu21
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
Date: Tue Mar 24 16:40:12 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
 Red Hat, Inc. Virtio GPU [1af4:1050] (rev 01) (prog-if 00 [VGA controller])
   Subsystem: Red Hat, Inc. Virtio GPU [1af4:1100]
InstallationDate: Installed on 2020-03-24 (0 days ago)
InstallationMedia: Xubuntu 20.04 LTS "Focal Fossa" - Alpha amd64 (20200324)
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 003: ID 0627:0001 Adomax Technology Co., Ltd QEMU USB Tablet
 Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU USB Keyboard
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/8p, 5000M
 /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/8p, 480M
     |__ Port 1: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 480M
     |__ Port 2: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 480M
MachineType: QEMU Standard PC (Q35 + ICH9, 2009)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-18-generic root=UUID=4b1c21e9-1325-435b-9ade-04263b901e6d ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/01/2014
dmi.bios.vendor: SeaBIOS
dmi.bios.version: rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-q35-4.2
dmi.modalias: dmi:bvnSeaBIOS:bvrrel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org:bd04/01/2014:svnQEMU:pnStandardPC(Q35+ICH9,2009):pvrpc-q35-4.2:cvnQEMU:ct1:cvrpc-q35-4.2:
dmi.product.name: Standard PC (Q35 + ICH9, 2009)
dmi.product.version: pc-q35-4.2
dmi.sys.vendor: QEMU
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.100-4
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.0-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.7-2ubuntu2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20190815-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

Mike Glover (mikeglover) wrote :
Ubuntu QA Website (ubuntuqa) wrote :

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:

tags: added: iso-testing
Daniel van Vugt (vanvugt) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

tags: added: virtio
summary: - Xubuntu 20.04 - Blank screen after login
+ [virtio] Xubuntu 20.04 - Blank screen after login
affects: xorg (Ubuntu) → xorg-server (Ubuntu)
Changed in xorg-server (Ubuntu):
status: New → Incomplete
Mike Glover (mikeglover) wrote :

I had to complete step 3 in order to get a crash file as step 1 had no crash files.
ID of newly-created bug is 1868930

Daniel van Vugt (vanvugt) wrote :

Thanks. I can't seem to access bug 1868930 so I guess it's probably private. I'll wait for the bots to process it and it should become public soon.

Mike Glover (mikeglover) wrote :

Had an email to say it is a duplicate of https://bugs.launchpad.net/bugs/1238747

So maybe thats why its private? Sorry I'm new to all this and learning. :)

Daniel van Vugt (vanvugt) wrote :

Bug 1238747 might be the cause of this bug, or it might be a separate unrelated crash. I don't know enough about XFCE to be able to tell.

Next please redo all the steps in comment #3 in case there is another different crash.

Mike Glover (mikeglover) wrote :

Not found anymore .crash files.

But I have found a workaround.

To reproduce the fix:

- Boot up the xubuntu machine in QuickEMU (Martin Wimpress QEMU script)

- Get to the login screen

- Change the session from Xubuntu to Xfce

- Type in password and Enter and the desktop appears as normal.

If Xubuntu session is selected I get the black screen.

Daniel van Vugt (vanvugt) wrote :


1. Reproduce the blank screen again and then immediately reboot. So the blank screen was the last issue near the end of the system log...

2. Now log in any way that avoids the blank screen so you can open a terminal and run:

   journalctl -b-1 > prevboot.txt

3. Attach the file 'prevboot.txt' here.

Mike Glover (mikeglover) wrote :

See attached:

Daniel van Vugt (vanvugt) wrote :

Thanks but for some reason that log is truncated and missing most of the boot. Please repeat the steps in comment #9.

Mike Glover (mikeglover) wrote :

Another prevboot file. I left the machine running with the black screen for longer.

Daniel van Vugt (vanvugt) wrote :

I can't see anything graphics-related happening or going wrong.

This sounds like a lightdm problem. Maybe this is it:

Mar 28 10:16:56 testvm lightdm[934]: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "test"

affects: xorg-server (Ubuntu) → lightdm (Ubuntu)
Changed in lightdm (Ubuntu):
status: Incomplete → New
To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers