Re: [PATCH 2/3 V3.1] can/usb: PEAK-System Technik PCAN-USB specific part

[Wolfgang Grandegger <wg@grandegger.com>]

On 01/20/2012 02:37 PM, Oliver Hartkopp wrote:
> On 20.01.2012 13:36, Wolfgang Grandegger wrote:
>> On 01/20/2012 01:34 PM, Wolfgang Grandegger wrote:
>>> Hi Oliver,
>>>
>>> On 01/20/2012 01:28 PM, Oliver Hartkopp wrote:
>>>
>>>> @Wolfgang: I always get "RTNETLINK answers: Device or resource busy"
>>>> when the device is up - even on the EMS PCMCIA card. Should the manual
>>>> restart generally be also possible even when the device is up??
>>>
>>> The restart is only for bus-off recovery. It will *not* restart if you
>>> are not in bus-off.
> 
> Ah, ok. Reading the *open* source helps :-))
> 
>>>> I think the automatic restart (with restart-ms) has no preconditions to
>>>> the device up/down state.
>>>
>>> But it only triggers in case of bus-off. It has nothing to do with up/down.
>>
>> If you are at it, please also test the bus-off and bus-off recovery...
>> Thanks...
> 
> Yes. Good point.
> 
> I set the PCAN-USB adapter (can2) to 100000 bit/s and let the two other
> nodes at 500kbit/s.
> 
> With low traffic at 500kbit and sending one frame from the PCAN-USB 
> (cansend can2 123#00) the bus-off is easy to reach on can2.
> 
> But the effect is:
> 
> I get every second(!) an error msg with
> 
>   can2  20000044  [8] 00 30 00 00 00 00 00 00   ERRORFRAME
>     controller-problem{rx-error-passive,tx-error-passive}
>     bus-off
> 
> But the state displayed in
> 
> ip -details -statistics link show can2 
> 
> always says 
> 
> 15: can2: <NO-CARRIER,NOARP,UP,ECHO> mtu 16 qdisc pfifo_fast state DOWN qlen 10
>     link/can
>     can state ERROR-ACTIVE restart-ms 0 
> 
> ... with increasing bus-off counter every second.
> 
> After setting the two other nodes at 100kbit/s too and do some traffic there, the
> state of the PCAN-USB should get back to work - but is does not.
> 
> The error msgs every second remain from can2.

The CAN error state is *not* handled at all in the driver :(. Obviously
I missed that. Stephane, could you please check error state changes to
error passive (no calble) and bus-off (short-circuit) and bus-off
recovery. "ip -d -s link show can0" and "candump any,0:0,#FFFFFFFF -e"
will give you useful information. Or even better, show use the output.

Thanks,

Wolfgang.