USB-C port doesn't work if nothing is connected at boot

User Support Hardware Issues
1

Thinkpad P51, which has one USB-C 3.1 port (Thunderbolt 3).
Qubes OS 4.2 fresh install.

If no device is connected to the USB-C port at the time of boot, then a flash drive or USB-C hub is not discovered when connecting it after the OS has started.

However, if a flash drive is connected at the time of boot, then it is shown in the list of devices, then it works fine, and I can attach it do individual VMs.

The following surprises me most: If an USB-C hub was connected to USB-C at the time of boot, then it works to hot-plug flash drives at Qubes runtime.

I wonder if there is a plausible explanation of this behavior, or if it seems like a hardware/BIOS bug.

I haven’t yet tried to boot a live USB system on that laptop, to check whether the behavior is the same with other Linux flavors.

2

Check the BIOS settings, there may be an option to only init the USB devices on boot time.

3

USB-A ports already work fine.
Only USB-C has that behavior.

4

Are there any options in BIOS related to Thunderbolt or USB-C specifically?

5

USB-A and USB-C are controlled independently. Read user manual. Snippet below . . .

After you install another operating system, you can enable the Thunderbolt 3 technology in ThinkPad Setup by doing the following:

1. Restart the computer and press F1 when the logo screen is displayed.
2. Select Config ➙ Thunderbolt™ 3 ➙ Security level.
3. Change the settings from Display Port and USB to any other selection.