Re: USB extension (repeater) cable
From: H. Peter Anvin
Date: Sun Jan 21 2007 - 02:18:40 EST
Greg KH wrote:
On Fri, Jan 19, 2007 at 04:40:34PM +0100, Udo van den Heuvel wrote:
Hello,
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
The second cable does the same.
Of course we have just one port on this hub...
Any ideas?
Perhaps the kernel is not lying and this cable really is bad? :)
Your hardware can not handle this device, there really is nothing that
the kernel can do about this.
USB extension cables are horrible things, and usually violate the USB
spec and do not always work, as you are finding out. Sorry about that.
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.
-hpa
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