I work with Ubuntu Studio 14.04 since an year, and I never had issues related to USB ports.
Now, since a week or so, all of my USB ports (two 2.0 and one 3.0) stopped working. Initially this happened only sometimes, and a reboot could fix it. Now, since three days, it happens all the times.
I know it's a linux problem and not an hardware one since I have a dual-boot (the other OS being Windows 8) and in Windows everything works fine. Also, in the boot screen I can see that the USB ports work since the red light in my mouse is lit, and it shuts down after I boot Ubuntu Studio.
Of course I want this to revert back to normal.
Do you have suggestions?
EDIT 1: (15/09/2015)
Further tests showed that while Linux version 3.13.0-61 always workss, both in generic and lowlatency mode, Linux version 3.13.0-62 and Linux version 3.13.0-63 usually don't, even though sometimes, randomly, they'll do. This happens both in lowlatency and generic modes.
I was suggested to upload a full output of sudo dmesg. Notice that apparently the terminal is not long enough to show all the message, but here's the output of a working 3.13.0-61 generic kernel, and here's the output of 3.13.0-63 lowlatency one.
EDIT 2: (16/09/2015)
Here's the complete output of sudo dmesg:
Here is the shortened version, with just the things referring to USB ports: