Re: USB EHCI Problem with Low Speed Devices on kernel 2.6.11+

From: Oliver Neukum
Date: Mon Aug 29 2005 - 02:55:57 EST




On Mon, 29 Aug 2005, James Courtier-Dutton wrote:

> Dominik Wezel wrote:
> > Problem
> > =======
> > When turning on the laptop and during POST and GrUB loading, all ports on
> > the hub are enabled. During the USB initialization phase, when the hub is
> > detected, shortly all ports become disabled, then turn on again (uhci_hcd
> > detects the lo-speed ports). Upon initialization of ehci_hcd however, the
> > ports are disconnected again (for good):
> >
>
> Use uhci_hcd or ehci_hcd, but never both at the same time.
> ehci_hcd will work with all lo-speed ports, so uhci_hcd is then no needed.

What? UHCI is stand alone. EHCI will work only with high speed devices
(that includes low and full speed on a high speed hub, but not directly
connected devices)

Regards
Oliver

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