Re: CAN-USB adapter unplug

[Jimmy Assarsson <extja@kvaser.com>]

On 2017-11-29 18:07, Martin Kelly wrote:
> On 11/29/2017 07:21 AM, Stefan Mätje wrote:
>> Am 29.11.2017 um 13:20 schrieb Marc Kleine-Budde:
>>> On 11/28/2017 10:09 PM, Martin Kelly wrote:
>>>>> Both applied to can.
>>>>
>>>> Thanks! By the way as far as I can tell from code inspection, it 
>>>> appears
>>>> that most of the other drivers in net/can/usb should have the same
>>>> disconnect bug. gs_usb appears to be clear, as it returns in its 
>>>> default
>>>> case. Unfortunately mcba_usb is the only device I have to test with, 
>>>> but
>>>> those with other devices may want to check for this.
>>>
>>> Can you create patches for the affected drivers and send them to the
>>> list and the maintainers of the driver on Cc?
>>>
>>> I don't have access to every USB adapter neither.
>>>
>>> Marc
>>>
>>
>> Hi,
>>
>> I have seen Martin's emails these days and tried to reproduce the 
>> error here
>> with an esd CAN-USB/2 device (handled by esd_usb2.c). The only thing I 
>> get
>> in the log are some messages like this:
>>
>> kernel: [14776.152459] usb 2-1: Rx URB aborted (-71)
>>
>> There is no endless loop. How could I reproduce the bad behavior? For the
>> quick test I used an Ubuntu 4.4.0-101-generic kernel.

Hi,

I got same result for kvaser_usb, a single "Rx URB aborted (-71)". When 
tested on Ubuntu with 4.4.0-93-generic.

> Interesting. Do you see just a few -71 RX URB aborted messages (one per 
> outstanding URB) rather than an endless loop? If so, then I think 
> everything is OK on that device, as the URBs are not being resubmitted.
> 
> In case it helps, my test case for the mcba_usb is on a Raspberry Pi 3. 
> I don't know whether or not that could influence the USB error code we 
> see, since you are seeing EPROTO instead of EPIPE when the device gets 
> unplugged.

However, I do get lots of (500+) "Rx URB aborted (-71)" printouts, on 
Raspberry Pi 3, running Raspbian with kernel 4.9.35-v7. But no EPIPE seen.

Regards,
Jimmy

>>
>> In any case I will add the patch handling EPIPE on a test system and 
>> have a
>> look what it might change.
>>
>> Regards,
>> Stefan Mätje