I had the same problem with a powered USB hub.
It didn't work (and made lsusb hang!) and gave the same -110 error in dmesg
Until I removed the power from the usb-hub and plugged it in again.
At that point the usb-hub still worked for my mice, (but not my external HD, because that required more power).
Then I could turn the power on and the hub kept working and the drive also started to work.
I've had a similar problem with my printer, which made Ubuntu not boot at all in the past, if it was turned on when booting.
But it wasn't until I had this issue with the hub (that works both with and without power) than I could see that enumaration fails on powered USB devices if they were powered on during boot.
SO, dear Kernel developers (that are no longer reading this bug, from what I gather) .. the issue is:
USB devices that are externally powered, block usb enumeration, if you attach them with the power plugged in.
iulian is right.
This is all related to POWER.
I had the same problem with a powered USB hub.
It didn't work (and made lsusb hang!) and gave the same -110 error in dmesg
Until I removed the power from the usb-hub and plugged it in again.
At that point the usb-hub still worked for my mice, (but not my external HD, because that required more power).
Then I could turn the power on and the hub kept working and the drive also started to work.
I've had a similar problem with my printer, which made Ubuntu not boot at all in the past, if it was turned on when booting.
But it wasn't until I had this issue with the hub (that works both with and without power) than I could see that enumaration fails on powered USB devices if they were powered on during boot.
SO, dear Kernel developers (that are no longer reading this bug, from what I gather) .. the issue is:
USB devices that are externally powered, block usb enumeration, if you attach them with the power plugged in.