Re: FAQ Somewhere? USB error messges

[Greg KH <greg@kroah.com>]

On Thu, Feb 19, 2009 at 04:59:28AM -0800, Yan Seiner wrote:
> Greg KH wrote:
>> On Wed, Feb 18, 2009 at 07:13:24PM -0800, Yan Seiner wrote:
>>   
>>> I have a device that has fallen off my usb hub.  It now refuses to 
>>> connect with:
>>>
>>> Feb 18 18:57:21 selene kernel: [217569.165436] usb 2-4.4.4.4.4.3: new low 
>>> speed USB device using ehci_hcd and address 55
>>> Feb 18 18:57:22 selene kernel: [217569.572035] usb 2-4.4.4.4.4.3: device 
>>> not accepting address 55, error -71
>>> Feb 18 18:57:22 selene kernel: [217569.572366] hub 2-4.4.4.4.4:1.0: 
>>> unable to enumerate USB device on port 3
>>>
>>> I'm fairly sure it's not the device as I have two identical ones that 
>>> work fine in other hubs.  I'm fairly sure it's not the hub as I have 
>>> other devices that work fine on that hub.
>>>
>>> So now I need to figure out what that error message means.  Where can I 
>>> look up the error code?
>>>     
>>
>> Documentation/usb/error-codes.txt
>>
>>   
> That says things like:
>
> -ENODEV         specified USB-device or bus doesn't exist
>
> -ENOENT         specified interface or endpoint does not exist or
>                is not enabled
>
>
> It has no information on translating 71 to E*.

That would be found in the include/asm-generic/errno.h file, as
EPROTO.

> Unfortunately that doesn't tell me what 71 is about. Grepping
> /usr/include for some of those errors *still* doesn't tell me what
> error 71 is as it doesn't appear anywhere.

See above.

> Is there any reason why the hotplug subsystem has to throw those cryptic 
> errors with no pointers to any docs where we might be able to decipher 
> them?

That's not the hotplug system, that's the kernel giving off those
messages.

> We're in userland; we don't deal with this on a daily basis, and we 
> have no clue where any of the info we need to understand those errors lies.

Hope the above information helped.

In short, it looks like you have a broken usb device, or not enough
power being sent to it.

good luck,

greg k-h