Comment 286 for bug 1667750

I've now managed to get a workable situation for myself:
Using an old USB2-hub instead of the USB3-hub that I was using before.

The DFU download takes ages when there is no hub between my computer and the STM32. Using the USB3-hub worked a few months ago when I was still on Ubuntu 16.04.

[ 5382.799225] usb 3-4.1: Product: ChibiOS/RT Virtual COM Port
[ 5382.799226] usb 3-4.1: Manufacturer: STMicroelectronics
[ 5382.799227] usb 3-4.1: SerialNumber: 400
[ 5382.807282] cdc_acm 3-4.1:1.0: ttyACM3: USB ACM device
[ 5387.003761] usb 3-4: clear tt 1 (91a1) error -32
About 12 identical messages in the same millisecond deleted.
[ 5387.004976] usb 3-4: clear tt 1 (91a1) error -32
[ 5387.222030] usb 3-4.1: USB disconnect, device number 22
[ 5387.224061] cdc_acm 3-4.1:1.0: failed to set dtr/rts
[ 5387.522299] usb 3-4.1: new full-speed USB device number 23 using xhci_hcd
[ 5387.627345] usb 3-4.1: New USB device found, idVendor=0483, idProduct=df11, bcdDevice=22.00
[ 5387.627348] usb 3-4.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 5387.627350] usb 3-4.1: Product: STM32 BOOTLOADER
[ 5387.627352] usb 3-4.1: Manufacturer: STMicroelectronics
[ 5387.627353] usb 3-4.1: SerialNumber: FFFFFFFEFFFF

So this is a mostly normal switchover from the usercode running ACM USB code and the bootloader. Through an USB2 switch.