For me, the sudo rmmod ehci_hcd workaround listed above will stop the external drive and the error messages temporarily, but then the drive and messages restart after a brief delay. Apparently the module has not reloaded at this point, because repeating the command yields
ERROR: Module ehci_hcd does not exist in /proc/modules
Reloading the module with sudo modprobe ehci_hcd has no effect, but then unloading the module again will stop the drive and messages again temporarily.
None of this allows me to actually mount the drive.
For me, the sudo rmmod ehci_hcd workaround listed above will stop the external drive and the error messages temporarily, but then the drive and messages restart after a brief delay. Apparently the module has not reloaded at this point, because repeating the command yields
ERROR: Module ehci_hcd does not exist in /proc/modules
Reloading the module with sudo modprobe ehci_hcd has no effect, but then unloading the module again will stop the drive and messages again temporarily.
None of this allows me to actually mount the drive.