The primary display will cause black screen when external 4K monitor is configured to flipped

[Woodrow Shen]

The primary (built-in) display will cause black screen when external 4K monitor is configured to flipped

Steps to reproduce:
1. plug 4K monitor via HDMI
2. open gnome-control-center
3. select Displays -> Orientation -> Landscape (flipped)
4. apply
5. black screen on built-in displays

The primary display can be recovered if HDMI cable is re-plugged again.

Machine:
Dell XPS 13 9380 (Intel Coffee Lake)

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27
Uname: Linux 5.4.0-21-generic x86_64
ApportVersion: 2.20.11-0ubuntu24
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Fri Apr 10 00:24:13 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation UHD Graphics 620 (Whiskey Lake) [8086:3ea0] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Dell UHD Graphics 620 (Whiskey Lake) [1028:08af]
InstallationDate: Installed on 2020-04-07 (2 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Beta amd64 (20200405)
MachineType: Dell Inc. XPS 13 9380
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-21-generic root=UUID=60712c21-4620-4018-821e-afb9a77f9ec8 ro quiet splash vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/15/2019
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 0.10.2
dmi.board.name: 0SSY11
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr0.10.2:bd01/15/2019:svnDellInc.:pnXPS139380:pvr:rvnDellInc.:rn0SSY11:rvrA00:cvnDellInc.:ct10:cvr:
dmi.product.family: XPS
dmi.product.name: XPS 13 9380
dmi.product.sku: 08AF
dmi.sys.vendor: Dell Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.100-4
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-1ubuntu1
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

[Woodrow Shen (woodrow-shen)]

This following message could happen when I repeated to switch landscape/flipped mode sometimes, but not always happened:
[ 3123.471] (WW) modeset(0): flip queue failed: Device or resource busy
[ 3123.471] (WW) modeset(0): Page flip failed: Device or resource busy

[Sebastien Bacher (seb128)]

Thank you for your bug report. Could you add your 'journalctl -b 0' log to the bug after getting the issue?

[Daniel van Vugt (vanvugt)]

The log messages in comment #2 make this sound like a bug in the Xorg modeset driver. To verify that please try logging in to 'Ubuntu on Wayland' instead.

[Woodrow Shen (woodrow-shen)]

Hi Daniel,

After logging with wayland, this bug is gone. Thanks for confirmation.