c_can: (newbie) high system load when frame not acked?

[Viktor Babrian <v@renyi.hu>]

Hi,

I am new to linux with can though I have had some experience with both 
separately.

I have here an am3359 board (having DCAN CAN controller). CAN transciever 
is terminated by a 60R resistor, no other party connected (no cables etc). 
I set up a can transmission using cansend:
# ip link set can1 type can bitrate 500000 triple-sampling on
# ip link set can1 up
# cansend can1 5A1#11.2233.44556677.88

Oscilloscope probe is on canh.

Everything works just fine, except:
- Frame is retransmitted for ever (seen on bus)
- user experience drops (serial terminal hardly echoes)
- load is up
- top shows sirq level of 75-80%

after bringing down can1 with
# ip link set can1 down,
I see that load is fine again (=0), however frame retransmission is going 
on still (observed by oscilloscope).
Transmission stops only after enabling can1 again:
# ip link set can1 up

Is this expected? Has anybody seen similar behavior?

I am using linux kernel 3.14.26. I have also tried c_can driver from 
3.19rc3 ("backported"=copied), same results.

Thanks in advance,
Viktor babrian