On Fri, 14 Dec 2007, Sergio Callegari wrote:

> What can I say... this is just excellent!!!
> And it works fine. I have tried and right after the unbinding my UMTS modem
> becomes visible.
> 
> So I have a rather elegant workaround for my issue.
> 
> Now the question is where the initial issue comes from:
> 1) Buggy hardware

Yes.

> 2) Some bug or missing feature in the ehci_hcd driver

No.

> Personally, I tend to believe that it should not be 1). In this days I have
> been looking on mailing lists and forums and there are by far too many
> people lamenting that they need to rmmod ehci_hcd to use their hardware
> (most of the complaints are related to kernels from 2.6.17 to 2.6.22).

You probably don't realize how much buggy hardware is being sold.  
It's a lot.  People aren't aware of the problems because "it seems to
work okay with Windows".  EHCI is the most complicated USB host
controller type, and the requirements for high-speed operation are more
stringent than the requirements for full or low speed; it's not
surprising that lots of devices have trouble.

> As far as I can I will try to pass the good news that they do not need to
> disable ehci alltogether.
> 
> Even if it is buggy hardware, I wonder if some some patch in the drivers might
> be possible since the thing just works in some other os.

There was a patch posted recently which might help:

http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/gregkh-03-usb/usb-force-handover-port-to-companion-when-hub_port_connect_change-fails.patch

Alan Stern

-
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to