Connection to USB-C hub frequently drops when charging over it

[Matt W.]

I am running Ubuntu 19.10 on a Lenovo Thinkpad X1 Extreme. I have a CalDigit TS3 Plus USB-C hub connected to one of the laptop's USB-C/Thunderbolt ports. The laptop supports charging over USB-C. When I try to charge from the hub over USB-C, Ubuntu seems to frequently "drop" the connection to the hub and loses connection to the stuff attached to the hub (e.g., an external monitor connected to the hub by USB-C to displayport, an ethernet connection, and USB devices). After a few seconds, the computer reconnects to these devices.

I disabled TLP but the problem persists.

When I have the laptop's power adapter attached in addition to the USB-C hub, the problem does not appear and the computer does not lose connection to the peripherals.

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: linux-image-5.3.0-23-generic 5.3.0-23.25
ProcVersionSignature: Ubuntu 5.3.0-23.25-generic 5.3.7
Uname: Linux 5.3.0-23-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu8.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC2: matt 2211 F.... pulseaudio
 /dev/snd/controlC1: matt 2211 F.... pulseaudio
 /dev/snd/controlC0: matt 2211 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Mon Nov 18 13:44:33 2019
InstallationDate: Installed on 2019-09-04 (75 days ago)
InstallationMedia: Ubuntu 19.04 "Disco Dingo" - Release amd64 (20190416)
MachineType: LENOVO 20MGS1YW00
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.3.0-23-generic root=UUID=3a5c73f9-5be3-4590-88a9-e362d949931c ro quiet splash resume=UUID=d464672d-224c-4149-a105-3a0cad515692 vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-5.3.0-23-generic N/A
 linux-backports-modules-5.3.0-23-generic N/A
 linux-firmware 1.183.2
SourcePackage: linux
UpgradeStatus: Upgraded to eoan on 2019-10-21 (28 days ago)
dmi.bios.date: 08/06/2019
dmi.bios.vendor: LENOVO
dmi.bios.version: N2EET42W (1.24 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20MGS1YW00
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:bvrN2EET42W(1.24):bd08/06/2019:svnLENOVO:pn20MGS1YW00:pvrThinkPadX1Extreme:rvnLENOVO:rn20MGS1YW00:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad X1 Extreme
dmi.product.name: 20MGS1YW00
dmi.product.sku: LENOVO_MT_20MG_BU_Think_FM_ThinkPad X1 Extreme
dmi.product.version: ThinkPad X1 Extreme
dmi.sys.vendor: LENOVO

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

This change was made by a bot.

[Kai-Heng Feng (kaihengfeng)]

Seems like it's a Thunderbolt Dock comes with Intel I210 ethernet?

[Matt W. (mw1234)]

I guess the manufacturer calls it a dock even though the computer does not actually dock into it, it attaches via a Thunderbolt 3 cable which I guess is different than USB-C . Sorry for the mistake.

This entry in the lspci:
40:00.0 Ethernet controller [0200]: Intel Corporation I210 Gigabit Network Connection [8086:1533] (rev 03)

is indeed over the dock (it disappears when the dock is unplugged; the other Ethernet controller remains so I guess it is the one in the laptop itself).

When I ran the info reporting program the only connections I had to the dock were an ethernet cable to the dock's ethernet port and an external monitor from a USB-C port on the dock to the displayport out on the monitor.

[Kai-Heng Feng (kaihengfeng)]

Please test latest mainline kernel:
https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.4-rc8/

Under v5.4-rc8, run
# echo "file drivers/pci/* +p" > /sys/kernel/debug/dynamic_debug/control

And attach dmesg when this issue happens again.

[Matt W. (mw1234)]

I tried installing the deb files

linux-headers-5.4.0-050400rc8_5.4.0-050400rc8.201911171930_all.deb
linux-headers-5.4.0-050400rc8-generic_5.4.0-050400rc8.201911171930_amd64.deb
linux-image-unsigned-5.4.0-050400rc8-generic_5.4.0-050400rc8.201911171930_amd64.deb
linux-modules-5.4.0-050400rc8-generic_5.4.0-050400rc8.201911171930_amd64.deb

and booting with the new kernel but my system did not seem to be wholly compatible. The proprietary nvidia drivers I am using (nvidia-driver-440 off of the Ubuntu graphics-drivers ppa) did not seem to be compatible with these kernel debs. I was unable to get to the Gnome desktop when trying to use nouveau drivers with kernel 5.4.0. I will try again and see if I can get to the desktop when I get a chance to debug the boot process in a day or two.

[Matt W. (mw1234)]

I am now running Ubuntu 20.04 with kernel version 5.4.0-37-generic and have reproduced the bug after running the command
 # echo "file drivers/pci/* +p" > /sys/kernel/debug/dynamic_debug/control
as was requested. Attached is the dmesg log.

Attached to the Thunderbolt hub are an iphone and an external monitor. The connection drops a couple times over the period of the log.