This change was made by a bot.
** Changed in: linux (Ubuntu)
Status: New => Confirmed
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https://bugs.launchpad.net/bugs/1908139
Title:
ThinkPad T14s external display not working on ThinkPad USB-C Dock Gen2
Status in linux package in Ubuntu:
Confirmed
Bug description:
laptop: ThinkPad T14s Gen 1 - AMD Ryzen 7 PRO 4750U
docking station: ThinkPad USB-C Dock 2. Gen.
external display: NE MultiSync EA275UHD
OS: Ubuntu 20.10 - kernel 5.8.0
Plugging the external display into one of the docking station's two
DisplayPort connectors leads to the screen resolution changing on the
laptop's builtin display and the external display waking up but
showing no picture and displaying "no-signal" after a bit.
Plugging the external display into the docking station's HDMI
connector leads to no visible reaction on either the external nor the
builtin display.
Plugging the external display into the laptop's builtin HDMI connector
works as expected. The external display is recognized and shows an
image.
I have recorded the output on `dmesg` during the steps mentioned above
and inserted explanations using `echo MSG >/dev/kmsg`. The output
follows at the end of the message. I believe `ubuntu-bug` should also
attach the full log.
All above modes of connection work as expected with the same laptop, dock,
and display on Windows 10 (installed as dual boot along side Ubuntu).
All above modes of connection also work as expected with an older laptop
(ThinkPad T470s - Ubuntu 20.04 - kernel 5.4.0), and the same dock and display.
This leads me to believe that this is not a hardware issue.
The following bug seems related, but seems to have been observed on
faulty hardware according to its author. Therefore, I decided to open
a separate bug report.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1899336
```
[ 343.372511] plugging DisplayPort into dock port 1
[ 352.666113] [drm] DP Alt mode state on HPD: 1
[ 352.749192] [drm] DM_MST: starting TM on aconnector: 000000002105a317 [id:
75]
[ 352.858482] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.888400] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.892555] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.896719] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.900876] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.905596] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.910323] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 352.914485] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 377.353566] plugged in - no signal
[ 396.728970] unplugging
[ 403.001418] [drm] DM_MST: stopping TM on aconnector: 000000002105a317 [id:
75]
[ 415.576397] unplugged
[ 431.500729] plugging DisplayPort into dock port 2
[ 437.607724] [drm] DP Alt mode state on HPD: 1
[ 437.681116] [drm] DM_MST: starting TM on aconnector: 000000002105a317 [id:
75]
[ 437.790303] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.820138] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.824305] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.828462] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.832619] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.837029] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.841984] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 437.846144] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 458.999849] plugged in - no signal
[ 465.702949] unplugging
[ 476.127418] [drm] DM_MST: stopping TM on aconnector: 000000002105a317 [id:
75]
[ 476.956491] [drm] Failed to add display topology, DTM TA is not
initialized.
[ 488.792533] unplugged
[ 529.801179] plugging HDMI into dock
[ 536.721076] [drm] DP Alt mode state on HPD: 1
[ 536.792947] [drm] DM_MST: starting TM on aconnector: 000000002105a317 [id:
75]
[ 536.901958] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.906123] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.910288] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.914611] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.919568] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.923725] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.927888] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.932047] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.936451] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.941486] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.945651] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 536.949808] [drm] amdgpu_dm_irq_schedule_work FAILED src 9
[ 537.010093] [drm:drm_dp_send_dpcd_read [drm_kms_helper]] *ERROR* mstb
00000000271ba325 port 1: DPCD read on addr 0x60 for 1 bytes NAKed
[ 592.844147] plugged in - display does not react
[ 597.998141] unplugging
[ 604.657060] [drm] DM_MST: stopping TM on aconnector: 000000002105a317 [id:
75]
[ 612.058516] unplugged
[ 630.409181] plugging HDMI into laptop
[ 637.125592] [drm] Failed to add display topology, DTM TA is not
initialized.
[ 639.077839] [drm] Failed to add display topology, DTM TA is not
initialized.
[ 639.192248] [drm] Failed to add display topology, DTM TA is not
initialized.
[ 683.221820] plugged in - working
[ 690.347738] unplugging
[ 694.212298] [drm] Failed to add display topology, DTM TA is not
initialized.
[ 725.466488] unplugged
```
ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: linux-image-5.8.0-33-generic 5.8.0-33.36
ProcVersionSignature: Ubuntu 5.8.0-33.36-generic 5.8.17
Uname: Linux 5.8.0-33-generic x86_64
ApportVersion: 2.20.11-0ubuntu50.2
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC2: aj 1262 F.... pulseaudio
/dev/snd/controlC1: aj 1262 F.... pulseaudio
/dev/snd/controlC3: aj 1262 F.... pulseaudio
/dev/snd/controlC0: aj 1262 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon Dec 14 22:11:01 2020
InstallationDate: Installed on 2020-12-12 (2 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
MachineType: LENOVO 20UHCTO1WW
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.8.0-33-generic
root=/dev/mapper/vgubuntu-root ro quiet splash vt.handoff=7
RelatedPackageVersions:
linux-restricted-modules-5.8.0-33-generic N/A
linux-backports-modules-5.8.0-33-generic N/A
linux-firmware 1.190.2
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/15/2020
dmi.bios.release: 1.25
dmi.bios.vendor: LENOVO
dmi.bios.version: R1CET56W(1.25 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20UHCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.ec.firmware.release: 1.25
dmi.modalias:
dmi:bvnLENOVO:bvrR1CET56W(1.25):bd09/15/2020:br1.25:efr1.25:svnLENOVO:pn20UHCTO1WW:pvrThinkPadT14sGen1:rvnLENOVO:rn20UHCTO1WW:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T14s Gen 1
dmi.product.name: 20UHCTO1WW
dmi.product.sku: LENOVO_MT_20UH_BU_Think_FM_ThinkPad T14s Gen 1
dmi.product.version: ThinkPad T14s Gen 1
dmi.sys.vendor: LENOVO
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