Bug report: External Thunderbolt-connected displays not reliably detected after sleep/wake.

[ndemarco]

External Thunderbolt-connected displays not reliably detected after sleep/wake.

Dell XPS13 9310
Plugable TBT3-UDC1 dock with supplied 0.8m 40 GB/s cable
2x Samsung LU28R55 monitors with HDMI to DisplayPort cables

Steps to reproduce:
1. Connect two LU28R55 monitors to TBT3-UDC1 dock using HDMI to DisplayPort cables and 40 GB/s 0.8m cable.
2. Observe both external monitors are detected and operate normally.
3. Allow PC to sleep normally, then wake from sleep.
Observe one monitor is not detected - remains in sleep mode (flashing power LED).
4. Exchange external monitor cables (at DisplayPort end).
Observe the problem stays with the port, not the monitor.
5. Move the TBT cable to an alternate laptop port (only two available on XPS13).
Observe different results for different occurrences of the problem:
a. Both monitors are detected. Desired result.
b. One monitor is detected.
c. Neither monitor is detected.

Note: I owned a previous generation XPS13 with iris graphics. This same issue occurred for a long time, then an unknown driver update (?) solved the problem. From memory, it was a Graphics driver, not TBT.

[ndemarco]

This technical article on the topic includes very little technical content.

[JosueO_Intel]

Hello ndemarco,

Thank you for posting on the Intel®️ communities.

In this case, we do not recommend the usage of any type of adapters or dockings since they can cause several issues such as compatibility issues which can cause the system to not work properly. Our recommendation is to check with Dell to verify the compatibility between your system and the docking that you have. 

Since the issue was solved previously by a driver update, we can try to verify the drivers installed in your system and check if there are any available updates that can help you solve the issue. 

In order to do that, please download and install the Intel®️ System Support Utility (Intel®️ SSU):

https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows- 

Open the application and select "Everything" click on "Scan" to see the system and device information. By default, Intel®️ SSU will take you to the "Summary View". Click on the menu where it says "Summary" to change to "Detailed View".  

Click on "Next", save the report and attach it to your response.

Regards, 

Josue O.  

Intel Customer Support Technician

[JosueO_Intel]

Hello ndemarco,

Were you able to check the previous post?  

Let us know if you still need assistance.  

Best regards,  

Josue O.  

Intel Customer Support Technician

[JosueO_Intel]

Hello ndemarco,

We have not heard back from you, so we will close this thread. If you need any additional information, please submit a new question as this thread will no longer be monitored. 

Best regards,  

Josue O. 

Intel Customer Support Technician