[LAU] Unbinding USB devices

Clemens Ladisch clemens at ladisch.de
Sun Feb 19 18:28:57 UTC 2017

Ralf Mardorf wrote:
> If I unbind the ehci device that shares the IRQ with audio cards, still
> all 10 available USB ports work
> Could somebody explain what this does mean?

EHCI controllers handle _only_ high-speed (USB 2.0) connections; full-
and low-speed connections require a separate controller (OHCI or UHCI).
You probably have a bunch of those.

> If I unbound ports on my old mobo, they stopped working.

Some chipsets have EHCI controllers with a built-in hub that handles
full-/low-speed connections, so for the OS, all connections end up at
the EHCI controller.


More information about the Linux-audio-user mailing list