Connecting a physical USB device to a virtual machine is sometimes tricky. Virtual machines are not really designed for physical interaction. In this case, it was necessary to mount a 1 TB external USB disk to a VMware virtual machine running Linux Mint 19.3. USB errors were seen and the disk would not connect. The fix was very simple.

Connecting the Disk

A USB disk was connected to a Linux laptop running VMware Workstation 15.5.1, and hosting a Linux Min 19.3 guest. When the connection “button” (at the bottom right of the VMware window) was pressed, these errors appeared in the guest’s kernel log:

[Tue Mar  3 22:51:30 2020] sched: RT throttling activated
[Tue Mar  3 22:58:17 2020] usb 1-1: new high-speed USB device number 6 using ehci-pci
[Tue Mar  3 22:58:18 2020] usb 1-1: device descriptor read/64, error 18
[Tue Mar  3 22:58:18 2020] usb 1-1: device descriptor read/64, error 18
[Tue Mar  3 22:58:18 2020] usb 1-1: new high-speed USB device number 7 using ehci-pci
[Tue Mar  3 22:58:19 2020] usb 1-1: device descriptor read/64, error 18
[Tue Mar  3 22:58:19 2020] usb 1-1: device descriptor read/64, error 18
[Tue Mar  3 22:58:19 2020] usb usb1-port1: attempt power cycle
[Tue Mar  3 22:58:20 2020] usb 1-1: new high-speed USB device number 8 using ehci-pci
[Tue Mar  3 22:58:20 2020] usb 1-1: Invalid ep0 maxpacket: 9
[Tue Mar  3 22:58:20 2020] usb 1-1: new high-speed USB device number 9 using ehci-pci
[Tue Mar  3 22:58:20 2020] usb 1-1: Invalid ep0 maxpacket: 9
[Tue Mar  3 22:58:20 2020] usb usb1-port1: unable to enumerate USB device
[Tue Mar  3 23:00:32 2020] pciehp 0000:00:15.0:pcie004: Slot(160): Attention 

USB Errors like this are very common. There are many causes and many potential solutions, some of them quite esoteric. In this case though, the solution was very simple.

Quick Solution

The fix was to edit the virtual machine settings in VMware, and change the USB specification from “USB 2.0” to “USB 3.0”. With that done, the disk connected without a problem. More explicitly:

VM settings -> USB Controller -> USB compatibility -> change USB 2.0 to USB 3.0.

The physical USB port was indeed USB 3, as was the external disk. One strange thing is that the arrangement (USB 2.0) had worked until a day or two earlier.

END.