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

[Oliver Hartkopp <oliver.hartkopp@volkswagen.de>]

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.

Regards,
Oliver