[i915] Plugging an external monitor on USB-C port does not show up. Need to reboot each time

[Hai NGUYEN VAN]

Whenever I plug an external monitor (Dell P2720DC) on my ThinkPad X1 (8th gen.) with Ubuntu 20.04, it is not directly recognized. I need to reboot the system so that it can find the monitor. Here is an extract of dmesg:

[87389.923632] usb 1-5: new high-speed USB device number 33 using xhci_hcd
[87390.072891] usb 1-5: New USB device found, idVendor=413c, idProduct=8442, bcdDevice= 1.00
[87390.072897] usb 1-5: New USB device strings: Mfr=0, Product=0, SerialNumber=1
[87390.072901] usb 1-5: SerialNumber: E9021071FBE1
[87390.073934] hub 1-5:1.0: USB hub found
[87390.074047] hub 1-5:1.0: 6 ports detected
[87390.367780] usb 1-5.5: new high-speed USB device number 34 using xhci_hcd
[87390.472473] usb 1-5.5: New USB device found, idVendor=0451, idProduct=82ff, bcdDevice= 2.00
[87390.472479] usb 1-5.5: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[87390.475022] hid-generic 0003:0451:82FF.0014: hiddev0,hidraw1: USB HID v1.11 Device [HID 0451:82ff] on usb-0000:00:14.0-5.5/input0

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.4.0-47.51-generic 5.4.55
Uname: Linux 5.4.0-47-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.8
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: skip
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
CurrentDesktop: Unity
Date: Wed Sep 16 09:40:10 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
EcryptfsInUse: Yes
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation UHD Graphics [8086:9b41] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Lenovo UHD Graphics [17aa:22be]
InstallationDate: Installed on 2020-08-24 (22 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
MachineType: LENOVO 20U9004PFR
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-47-generic root=UUID=4a93b148-f388-4849-9a18-9e0e4d32c97a ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/01/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: N2WET19W (1.09 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20U9004PFR
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN2WET19W(1.09):bd07/01/2020:svnLENOVO:pn20U9004PFR:pvrThinkPadX1CarbonGen8:rvnLENOVO:rn20U9004PFR:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad X1 Carbon Gen 8
dmi.product.name: 20U9004PFR
dmi.product.sku: LENOVO_MT_20U9_BU_Think_FM_ThinkPad X1 Carbon Gen 8
dmi.product.version: ThinkPad X1 Carbon Gen 8
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.8-0ubuntu1~20.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx 20.0.8-0ubuntu1~20.04.1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2.4
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+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.