Re: [GIT PULL] USB driver fixes for 3.18-rc7

[Mathias Nyman]

On 02.12.2014 20:18, Greg KH wrote:
> On Sun, Nov 30, 2014 at 11:47:20AM -0800, Linus Torvalds wrote:
>> Hmm, Greg.
>>
>> I seem to get this problem possibly more commonly at boot these days:
>>
>>   usb 1-6: new full-speed USB device number 2 using xhci_hcd
>>   usb 1-6: device descriptor read/64, error -71
>>   xhci_hcd 0000:00:14.0: Setup ERROR: setup context command for slot 1.
>>   usb 1-6: hub failed to enable device, error -22
>>   usb 1-6: new full-speed USB device number 3 using xhci_hcd
>>   usb 1-6: device descriptor read/64, error -71
>>   usb 1-6: hub failed to enable device, error -22
>>   usb 1-6: new full-speed USB device number 4 using xhci_hcd
>>   usb 1-6: Device not responding to setup address.
>>   usb 1-6: Device not responding to setup address.
>>   usb 1-6: device not accepting address 4, error -71
>>   usb 1-6: new full-speed USB device number 5 using xhci_hcd
>>   usb 1-6: Device not responding to setup address.
>>   usb 1-6: Device not responding to setup address.
>>   usb 1-6: device not accepting address 5, error -71
>>  usb usb1-port6: unable to enumerate USB device
>>
>> and my keyboard doesn't work. I then unplug and re-plug it, and get
>>
>>   usb 1-6: new full-speed USB device number 9 using xhci_hcd
>>   usb 1-6: New USB device found, idVendor=2516, idProduct=0020
>>   usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=0
>>   usb 1-6: Product: Quickfire Rapid i
>>   usb 1-6: Manufacturer: CM Storm
>>
>> Any ideas? Some setup delay that isn't long enough at boot time for a
>> slightly finicky device? It has happened before, but now I've gotten
>> it twice within a couple of days:
>>
>>   Nov 02 12:18:56 i7.lan kernel: usb 1-6: device descriptor read/64, error -71
>>   Nov 28 16:54:06 i7.lan kernel: usb 1-6: device descriptor read/64, error -71
>>   Nov 30 11:26:35 i7.lan kernel: usb 1-6: device descriptor read/64, error -71
>>
>> (I've had this keyboard since mid-September, and looking at the logs
>> this machine has been rebooted 41 times since, with those three
>> failures..)
> 
> I've been seeing this occasionally recently as well, but was blaming a
> "bad" USB 3 hub I have here that I use, and the problem goes away with a
> replug.
> 
> Mathias, any ideas what is going on here?
> 

Looks like when xhci changed to use "new scheme" device enumeration for non
SuperSpeed devices, we broke the device descriptor read retry for xhci.

Normally we try to read the descriptor again, and if it still fails then fall back
to old scheme. In this failing xhci case the slot is left in a default state after
first failed descriptor read, and we then try to enable the slot again in retry, 
which is an invalid xhci context state change, and prints the error message:

xhci_hcd 0000:00:14.0: Setup ERROR: setup context command for slot 1

After this It might be hard to get the device addressed. 

I don't know why it fail the first device descriptor read, but fixing the xhci part
should allow more real reties. I'll work on it.

The change to use xhci "new scheme" enumeration was done in 3.14 to support known
legacy devices requiring it. commit 48fc7dbd52c0559647291f33a10ccdc6cdbe4c72

-Mathias
 
> greg k-h
> 
>>
>>               Linus

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