Bug 217674 - Thunderbolt dock does not recognize displays connected via DP->HDMI cable
Summary: Thunderbolt dock does not recognize displays connected via DP->HDMI cable
Status: NEW
Alias: None
Product: Drivers
Classification: Unclassified
Component: USB (show other bugs)
Hardware: AMD Linux
: P3 normal
Assignee: Default virtual assignee for Drivers/USB
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-07-16 09:10 UTC by Andew Marshall
Modified: 2023-07-17 19:37 UTC (History)
2 users (show)

See Also:
Kernel Version:
Subsystem:
Regression: No
Bisected commit-id:


Attachments
lspci -v output (14.75 KB, text/plain)
2023-07-16 09:10 UTC, Andew Marshall
Details
journalctl --dmesg output (173.75 KB, text/plain)
2023-07-16 09:17 UTC, Andew Marshall
Details
kernel config (257.92 KB, text/plain)
2023-07-16 09:18 UTC, Andew Marshall
Details

Description Andew Marshall 2023-07-16 09:10:35 UTC
Created attachment 304641 [details]
lspci -v output

Summary
-------

When using a thunderbolt dock with 2x DisplayPort connectors, the displayys are not recognized when connected with DP->HDMI cables. Connecting over DP->DP cables work as expected.

Expected Behaviour
------------------

Displays connected to the dock via DP->HDMI cables should be recognized.

Actual Behaviour
----------------

Displays connected to the dock via DP->HDMI cables are not recognized. The following messages are reported in `dmesg`

```
[68022.156971] thunderbolt 0-2: new device found, vendor=0x6f device=0x12
[68022.156977] thunderbolt 0-2: StarTech.com TB3CDK2DP
...various USB connection messages...
[68139.834086] [drm] DMUB HPD callback: link_index=2
[68139.834859] [drm] DPIA AUX failed on 0x0(1), error 3
[68139.836167] [drm] DPIA AUX failed on 0x0(1), error 3
(etc)
```
USB ports and network connection functions as expected.


Steps to Reproduce
------------------

Laptop used is Asus G14 (2023) model GA402NV
Dock is Startech TB3CDK2DP
Reproduced on Linux Kernel 6.4.3 from stable repo

1. Connect laptop to dock over USB-C
2. Connect an external display with DP->HDMI cable
3. Open appropriate display settings to see if external display is recognized.
Comment 1 Andew Marshall 2023-07-16 09:17:53 UTC
Created attachment 304642 [details]
journalctl --dmesg output
Comment 2 Andew Marshall 2023-07-16 09:18:33 UTC
Created attachment 304643 [details]
kernel config
Comment 3 Bagas Sanjaya 2023-07-16 11:15:58 UTC
(In reply to Andew Marshall from comment #0)
> Created attachment 304641 [details]
> lspci -v output
> 
> Summary
> -------
> 
> When using a thunderbolt dock with 2x DisplayPort connectors, the displayys
> are not recognized when connected with DP->HDMI cables. Connecting over
> DP->DP cables work as expected.
> 
> Expected Behaviour
> ------------------
> 
> Displays connected to the dock via DP->HDMI cables should be recognized.
> 
> Actual Behaviour
> ----------------
> 
> Displays connected to the dock via DP->HDMI cables are not recognized. The
> following messages are reported in `dmesg`
> 
> ```
> [68022.156971] thunderbolt 0-2: new device found, vendor=0x6f device=0x12
> [68022.156977] thunderbolt 0-2: StarTech.com TB3CDK2DP
> ...various USB connection messages...
> [68139.834086] [drm] DMUB HPD callback: link_index=2
> [68139.834859] [drm] DPIA AUX failed on 0x0(1), error 3
> [68139.836167] [drm] DPIA AUX failed on 0x0(1), error 3
> (etc)
> ```
> USB ports and network connection functions as expected.
> 
> 
> Steps to Reproduce
> ------------------
> 
> Laptop used is Asus G14 (2023) model GA402NV
> Dock is Startech TB3CDK2DP
> Reproduced on Linux Kernel 6.4.3 from stable repo
> 
> 1. Connect laptop to dock over USB-C
> 2. Connect an external display with DP->HDMI cable
> 3. Open appropriate display settings to see if external display is
> recognized.

Do you have this issue on v6.1 stable series?
Comment 4 Andew Marshall 2023-07-16 20:46:54 UTC
(In reply to Bagas Sanjaya from comment #3)

> 
> Do you have this issue on v6.1 stable series?

I tried v6.1 and I get the same issue, although there are no drm errors in the log. Just the one message:

```
[  214.332514] [drm] DMUB HPD callback: link_index=2
```
Comment 5 Mario Limonciello (AMD) 2023-07-17 19:37:57 UTC
This is very likely a GPU driver or GPU microcode bug.  Can you please bring the issue to https://gitlab.freedesktop.org/drm/amd/-/issues

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