Comment 30 for bug 522998

I was getting the messages:
pm_op(): usb_dev_freeze+0x0/0x20 returns -2
PM: Device usb9 failed to freeze async: error -2

This is an usb 3.0 port on a new computer with Ubuntu 10.10

The proposed workaround:
create files : /etc/pm/config.d/00sleep_module and /etc/pm/config.d/unload_module
add line to files : SUSPEND_MODULES="xhci"

did not work for me.

This post caught my eye:
d3mia7 wrote on 2010-05-05: #11
Note that the module has been renamed "xhci_hcd" in the latest mainline kernel (2.6.34-rc6).

There is a typo in this post. The module has been renamed to "xhci-hcd", not "xhci_hcd".

This workaround fixes the problem for me:
create files : /etc/pm/config.d/00sleep_module and /etc/pm/config.d/unload_module
add line to files : SUSPEND_MODULES="xhci-hcd"