USB to Serial adapter doesn't works
I've found that my Serial-to-USB converter (ch341-uart) doesn't works with USB 3.0 ports. Unfortunately, my HP Envy doesn't have a USB 2.0 hub, all ports are reported as USB 3.0 ports to OS. Seems like this device isn't supported under USB 3.0. However, I've got a USB 2.0 hub. If I connect this hub to any port, and then connect the Serial converter to this hub, it works OK, even using xhci_hcd:
Sep 13 10:36:36 envy4 kernel: [ 1852.477261] usb 3-3: new high-speed USB device number 53 using xhci_hcd
Sep 13 10:36:36 envy4 kernel: [ 1852.493499] usb 3-3: New USB device found, idVendor=1a40, idProduct=0101
Sep 13 10:36:36 envy4 kernel: [ 1852.493504] usb 3-3: New USB device strings: Mfr=0, Product=1, SerialNumber=0
Sep 13 10:36:36 envy4 kernel: [ 1852.493508] usb 3-3: Product: USB 2.0 Hub
Sep 13 10:36:36 envy4 kernel: [ 1852.493811] hub 3-3:1.0: USB hub found
Sep 13 10:36:36 envy4 kernel: [ 1852.493842] hub 3-3:1.0: 4 ports detected
Sep 13 10:36:37 envy4 kernel: [ 1852.781193] usb 3-3.1: new full-speed USB device number 54 using xhci_hcd
Sep 13 10:36:37 envy4 kernel: [ 1852.798586] usb 3-3.1: New USB device found, idVendor=4348, idProduct=5523
Sep 13 10:36:37 envy4 kernel: [ 1852.798592] usb 3-3.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
Sep 13 10:36:37 envy4 kernel: [ 1852.799069] ch341 3-3.1:1.0: ch341-uart converter detected
Sep 13 10:36:37 envy4 kernel: [ 1852.800220] usb 3-3.1: ch341-uart converter now attached to ttyUSB0