[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: USB drivers in FC5



Glenn Lawyer wrote:
> How do I get FC5 to use the ohci_hcd usb driver by default, instead of 
> ehci_hcd?
> 
> I just rebuilt my system from the motherboard up, migrating from 32 bit to 64 
> bit (AMD). Thought this a good opportunity to update from FC4 to FC5, which 
> went smoothly using the DVD image.
> 
> Discovered that USB drives were no longer detected. Tracked it down to a usb 
> driver problem. Current solution is to su -c "modprobe -r ehci_hcd"
> after every boot-up. (and yes, I do like to shut my machine off at
> night, for the sake of my mental health.)

OHCI and UHCI were competing standards for how to program a USB 1.1
controller. EHCI is the standard for USB 2.0 controllers.

This means that by removing EHCI, you're downgrading your USB drives
from a USB 2.0 (480 Mbit/s) connection to a USB 1.1 (12 Mbit/s)
connection.

I have a similar problem with my motherboard. If I plug in a USB drive
at the back of the case, it works fine. If I plug it in the front USB
sockets, it -- erm -- doesn't. Unless *I* rmmod ehci_hcd. Then it works
fine, at 12 Mbit/s. I suspect that the case USB connections don't
support 480 Mbit/s.

My solution is a separate USB cable...

Hope this helps,

James.

-- 
E-mail address: james | Helpful Advice from Thames Water:
@westexe.demon.co.uk  | "If you have difficulty reading this leaflet,
                      | please ask someone to help you."
                      |     -- Read on "The News Quiz", BBC Radio 4


[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]