Re: USB extension (repeater) cable

From: Udo van den Heuvel
Date: Sun Jan 21 2007 - 02:20:43 EST


H. Peter Anvin wrote:
> Greg KH wrote:
>> On Fri, Jan 19, 2007 at 04:40:34PM +0100, Udo van den Heuvel wrote:
>>>
>>> I just tried my shiny new usb extension cable (repeater):
>>>
>>> Jan 19 16:01:17 epia kernel: usb 5-1: new high speed USB device using
>>> ehci_hcd and address 60
>>> Jan 19 16:01:17 epia kernel: usb 5-1: configuration #1 chosen from 1
>>> choice
>>> Jan 19 16:01:17 epia kernel: hub 5-1:1.0: USB hub found
>>> Jan 19 16:01:17 epia kernel: hub 5-1:1.0: 4 ports detected
>>> Jan 19 16:01:18 epia kernel: hub 5-1:1.0: Cannot enable port 1. Maybe
>>> the USB cable is bad?
>>> Jan 19 16:01:22 epia last message repeated 3 times
>>> Jan 19 16:01:23 epia kernel: hub 5-1:1.0: Cannot enable port 2. Maybe
>>> the USB cable is bad?
>>> Jan 19 16:01:26 epia last message repeated 3 times
>>> Jan 19 16:01:27 epia kernel: hub 5-1:1.0: Cannot enable port 3. Maybe
>>> the USB cable is bad?
>>> Jan 19 16:01:31 epia last message repeated 3 times

[...]

> Actually, what it looks like is even simpler. The extension cable
> contains a four-port hub chip (which is the most common commodity chip)
> and haven't bothered changing the descriptor to tell the computer only
> one port is actually active. So only one port can be activated, and the
> others are stubbed out in some evil way. In that case, it should be
> noisy but harmless.

I will do some more testing then.
Is there a way to get rid of the messages?
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