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LoNaAleim

Member

Registered: 2020-05-20

Posts: 33

[SOLVED] WD19TB + Thunderbolt screen: Link Training Unsuccessful

Setup:
Dell XPS 13 2 in 1 7390 Laptop
Dell WD19TB Thunderbolt dock
Asus Zenscreen GO MB16AP Portable Thunderbolt monitor

What I want:
Use the Zenscreen on the go (Trains) plugged directly into my laptop.
Use the Zenscreen plugged into the thunderbolt out of the Dock when I have a "semi-permanent" setup. (At a hotel room / parents house)
Whilst plugging the dock into my laptop.
This setup worked perfectly fine under Windows on my HP Spectre x360, life was beautiful.

Fast forward a few months, I switch to arch Linux and get this Dell laptop.
Using the laptop with the screen directly plugged in -> Works like a charm.
Using it "through" the Dock: Nope, screen not recognized (checked using xrandr)
I didn't bother too much because the Dock + Laptop is a Horrorshow anyway. See: https://gitlab.freedesktop.org/drm/intel/-/issues/1453

Fast forward a few more months: (today)
I try the screen through the dock thing again: It works! BUT: I can set the resolution of the screen only up to something like 1024xSomething (don't remember the exact numbers).
Added an xrandr profile generated with:

gtf 1920 1080 60

, but when I select it, it fails:

xrandr: Configure crtc 1 failed

It gets me thinking: Hey, maybe the generated profile is not quite right. If I plug the monitor directly into the laptop, I can check the profile it uses there and "transfer it" over when connecting through the dock.
I plug the monitor directly into the laptop, works instantly on full resolution. I grab the profile info via

xrandr --verbose

Plug the monitor back into the dock: Screen is not recognized, and no amount of re-plugging and re-booting and

xrandr -s 0

gets this to work again.
In fact, in order to make the monitor work with the laptop at all, I need to plug it in first, then the dock.

Which leads me to the first big question: Even though the wiki states:

xrandr is just a simple interface to the RandR extension and has no configuration file. However, there are multiple ways of achieving persistent configuration:

The system must have stored some information about the monitor when it was plugged in directly that is now keeping it from working when plugged in via the dock, no?
I can't find any corresponding file, tho. There is no

.config/monitors.xml

and nothing in my

/etc/X11/xorg.conf.d

?

Second question:
Any hints on making this work as I want it to?

Last edited by LoNaAleim (2020-12-20 12:18:54)

yaworski

Member

Registered: 2018-08-05

Posts: 41

Re: [SOLVED] WD19TB + Thunderbolt screen: Link Training Unsuccessful

Unfortunately whole series of Dell laptops based on Intel IceLake-U CPUs is affected by this. There's a thread regarding this issues already: https://bbs.archlinux.org/viewtopic.php?id=255925

---edit---

I should've checked first . You're also the author of the original thread.

Last edited by yaworski (2020-11-26 08:09:55)

LoNaAleim

Member

Registered: 2020-05-20

Posts: 33

Re: [SOLVED] WD19TB + Thunderbolt screen: Link Training Unsuccessful

So yesterday I accidentally plugged the monitor into the dock again, and the good news is: The screen came on. The bad news is: Still limited to 1024x768.
But, I checked dmesg, and look what I found:

[Mi Nov 25 13:08:04 2020] usb 5-1: new high-speed USB device number 7 using xhci_hcd
[Mi Nov 25 13:08:04 2020] usb 5-1: New USB device found, idVendor=0bda, idProduct=5412, bcdDevice= 1.41
[Mi Nov 25 13:08:04 2020] usb 5-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[Mi Nov 25 13:08:04 2020] usb 5-1: Product: 4-Port USB 2.0 Hub
[Mi Nov 25 13:08:04 2020] usb 5-1: Manufacturer: Generic
[Mi Nov 25 13:08:04 2020] hub 5-1:1.0: USB hub found
[Mi Nov 25 13:08:04 2020] hub 5-1:1.0: 2 ports detected
[Mi Nov 25 13:08:05 2020] usb 6-1: new SuperSpeed Gen 1 USB device number 5 using xhci_hcd
[Mi Nov 25 13:08:05 2020] usb 6-1: New USB device found, idVendor=0bda, idProduct=0412, bcdDevice= 1.41
[Mi Nov 25 13:08:05 2020] usb 6-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[Mi Nov 25 13:08:05 2020] usb 6-1: Product: 4-Port USB 3.0 Hub
[Mi Nov 25 13:08:05 2020] usb 6-1: Manufacturer: Generic
[Mi Nov 25 13:08:05 2020] hub 6-1:1.0: USB hub found
[Mi Nov 25 13:08:05 2020] hub 6-1:1.0: 2 ports detected
[Mi Nov 25 13:08:05 2020] usb 5-1.2: new full-speed USB device number 8 using xhci_hcd
[Mi Nov 25 13:08:05 2020] usb 5-1.2: not running at top speed; connect to a high speed hub
[Mi Nov 25 13:08:05 2020] usb 5-1.2: New USB device found, idVendor=0bda, idProduct=5400, bcdDevice= 1.06
[Mi Nov 25 13:08:05 2020] usb 5-1.2: New USB device strings: Mfr=17, Product=18, SerialNumber=19
[Mi Nov 25 13:08:05 2020] usb 5-1.2: Product: BillBoard Device
[Mi Nov 25 13:08:05 2020] usb 5-1.2: Manufacturer: Realtek
[Mi Nov 25 13:08:05 2020] usb 5-1.2: SerialNumber: 123456789ABCDEFGH
[Mi Nov 25 13:08:05 2020] usb 6-1.1: new SuperSpeed Gen 1 USB device number 6 using xhci_hcd
[Mi Nov 25 13:08:05 2020] usb 6-1.1: New USB device found, idVendor=17e9, idProduct=4375, bcdDevice=31.01
[Mi Nov 25 13:08:05 2020] usb 6-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[Mi Nov 25 13:08:05 2020] usb 6-1.1: Product: MB16AP
[Mi Nov 25 13:08:05 2020] usb 6-1.1: Manufacturer: DisplayLink
[Mi Nov 25 13:08:05 2020] usb 6-1.1: SerialNumber: 4540490M0892
[Mi Nov 25 13:08:10 2020] i915 0000:00:02.0: [drm] *ERROR* Link Training Unsuccessful <- GOTCHA
[Mi Nov 25 13:08:11 2020] usb 6-1.1: USB disconnect, device number 6

Now, for reference, here is what happens when I plug the screen directly into the laptop:

[Do Nov 26 21:45:00 2020] usb 3-8: new high-speed USB device number 11 using xhci_hcd
[Do Nov 26 21:45:00 2020] usb 3-8: New USB device found, idVendor=0bda, idProduct=5412, bcdDevice= 1.41
[Do Nov 26 21:45:00 2020] usb 3-8: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[Do Nov 26 21:45:00 2020] usb 3-8: Product: 4-Port USB 2.0 Hub
[Do Nov 26 21:45:00 2020] usb 3-8: Manufacturer: Generic
[Do Nov 26 21:45:00 2020] hub 3-8:1.0: USB hub found
[Do Nov 26 21:45:00 2020] hub 3-8:1.0: 2 ports detected
[Do Nov 26 21:45:00 2020] usb 2-1: new SuperSpeed Gen 1 USB device number 17 using xhci_hcd
[Do Nov 26 21:45:00 2020] usb 2-1: New USB device found, idVendor=0bda, idProduct=0412, bcdDevice= 1.41
[Do Nov 26 21:45:00 2020] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[Do Nov 26 21:45:00 2020] usb 2-1: Product: 4-Port USB 3.0 Hub
[Do Nov 26 21:45:00 2020] usb 2-1: Manufacturer: Generic
[Do Nov 26 21:45:00 2020] hub 2-1:1.0: USB hub found
[Do Nov 26 21:45:00 2020] hub 2-1:1.0: 2 ports detected
[Do Nov 26 21:45:00 2020] usb 3-8.2: new full-speed USB device number 12 using xhci_hcd
[Do Nov 26 21:45:00 2020] usb 2-1.1: new SuperSpeed Gen 1 USB device number 18 using xhci_hcd
[Do Nov 26 21:45:00 2020] usb 2-1.1: New USB device found, idVendor=17e9, idProduct=4375, bcdDevice=31.01
[Do Nov 26 21:45:00 2020] usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[Do Nov 26 21:45:00 2020] usb 2-1.1: Product: MB16AP
[Do Nov 26 21:45:00 2020] usb 2-1.1: Manufacturer: DisplayLink
[Do Nov 26 21:45:00 2020] usb 2-1.1: SerialNumber: 4540490M0892
[Do Nov 26 21:45:00 2020] usb 3-8.2: not running at top speed; connect to a high speed hub
[Do Nov 26 21:45:00 2020] usb 3-8.2: New USB device found, idVendor=0bda, idProduct=5400, bcdDevice= 1.06
[Do Nov 26 21:45:00 2020] usb 3-8.2: New USB device strings: Mfr=17, Product=18, SerialNumber=19
[Do Nov 26 21:45:00 2020] usb 3-8.2: Product: BillBoard Device
[Do Nov 26 21:45:00 2020] usb 3-8.2: Manufacturer: Realtek
[Do Nov 26 21:45:00 2020] usb 3-8.2: SerialNumber: 123456789ABCDEFGH
[Do Nov 26 21:45:02 2020] usb 2-1.1: USB disconnect, device number 18

I will adjust the title to the "narrowed down" issue.

I suspect I should take this upstream to the i915 guys?

Last edited by LoNaAleim (2020-11-26 21:00:17)

LoNaAleim

Member

Registered: 2020-05-20

Posts: 33

Re: [SOLVED] WD19TB + Thunderbolt screen: Link Training Unsuccessful

Tested it on Ubuntu today, same error. Took it upstream: https://gitlab.freedesktop.org/drm/intel/-/issues/2737

LoNaAleim

Member

Registered: 2020-05-20

Posts: 33

Re: [SOLVED] WD19TB + Thunderbolt screen: Link Training Unsuccessful

Further digging: (Check the issue linked earlier for the full picture)
When plugged into the dock, the screen has these additional attributes in `xrandr --verbose`

HDCP Content Type: HDCP Type0 
	supported: HDCP Type0, HDCP Type1
Content Protection: Undesired 
	supported: Undesired, Desired, Enabled

So, as far as  I understand HDCP, it tries to "assure" that there is a "trusted" device on the other end, otherwise it falls back to a lower resolution, in order to prevent people from recording high quality content.
So maybe my dock is identified as a "man in the middle" that could be a recording device and thus the low resolution?
Now: Is this implemented in the monitor or in the kernel?
Can I disable this crap somehow?

Last edited by LoNaAleim (2020-12-01 16:26:51)

LoNaAleim

Member

Registered: 2020-05-20

Posts: 33

Re: [SOLVED] WD19TB + Thunderbolt screen: Link Training Unsuccessful

I just discovered that this dock has an additional Displayport Type-C Plug at the back. Plugged the screen in there and it worked.
Marking this as solved, but keeping the issue at drm open since its supposed to work on both plugs as far as I understand.