RTCan missing frames

Johannes Holtz johannes.holtz at compador.de
Tue Feb 12 15:38:50 CET 2019


Am 12.02.19 um 12:24 schrieb Wolfgang Grandegger:
> Hello,
>
> Am 12.02.19 um 11:42 schrieb Johannes Holtz:
>> Am 11.02.19 um 17:46 schrieb Wolfgang Grandegger:
> ... snip ...
>>> UI suggest to write a simple test program to demonstrate the issue. It
>>> should just open the socket and trying to receive messages... just the
>>> necessary stuff. First with a blocking recv() and then non-blocking.
>>>
>>> What hardware and software are you using (arch, board, linux, xenomai)?
> ?
>
>>> Wolfgang.
>> The source code is attached:
>>
>> compiled with -I/opt/xenomai/include -D_GNU_SOURCE -D_REENTRANT
>> -D__XENO__ -lrtdm -L/opt/xenomai/lib -lxenomai -lpthread -lrt -lnative
>>
>> can frames sent by rtcansend
>>
>> Test 1: blocking:
>>
>> ID:0 DLC:2hex:  81 00       <-- NMT request
>> ID:709 DLC:1hex:  00        <-- answer node #9
>> ID:708 DLC:1hex:  00        <-- answer node #8
>> ID:703 DLC:1hex:  00        <-- answer node #3
>> ID:705 DLC:0hex:             <-- here it gets weird ! DLC == 0
>> ID:70400 DLC:1hex:  01
>> ID:70600 DLC:1hex:  01
>> ID:70100 DLC:1hex:  01
>> ID:70200 DLC:1hex:  01
>> ID:1010000 DLC:1hex:  08
> This means that you can receive messages from the CAN bus.
>
>> ID:53220 DLC:124 out of bounds. abort.
> But that's wired.
>
>> Test 2: non blocking:
>>
>> ID:0 DLC:2hex:  81 00    <-- NMT request
>> ID:709 DLC:1hex:  00     <-- answer node #9
>> ID:708 DLC:1hex:  00     <-- answer node #8
>> ID:703 DLC:1hex:  00     <-- answer node #3
>> ID:705 DLC:0hex:          <-- same issue DLC is 0
>> ID:70600 DLC:1hex:  01
>> ID:70400 DLC:1hex:  01
>> ID:70200 DLC:1hex:  01
>> ID:70100 DLC:1hex:  01
>> ID:1010000 DLC:1hex:  08
>> ID:53220 DLC:124 out of bounds. abort.
> Looks identical.
>
>> Also, I found another possible error source and I don't know if this
>> error picture would corresponds to this.
>>
>> However,  While reviewing all settings, I noticed that I made a mistake
>> with the RXBUF_SIZE which is set to 8096 instead of 8192. Must have been
>> asleep when writing this. I'm going to rebuild this module.
> Let's try to understand why rt_dev_recv() does return bogus dlc.
>
> What hardware and software are you using (arch, board, can controlelr,
> linux, xenomai)?
>
> Wolfgang.

I modified the program a little to send it's own requests via one single 
socket. The output look like this.

send succeeded
ID:708 DLC:1hex:  00
ID:709 DLC:1hex:  00
ID:703 DLC:1hex:  00
ID:706 DLC:1hex:  00
ID:705 DLC:7hex:  00 00 01 01 00 09 07
send succeeded
send succeeded
send succeeded
send succeeded
send succeeded

And a parallel rtcanrecv output  like this:

root at machinectrl:~# rtcanrecv rtcan0
#0: (1) <0x000> [2] 81 00
#1: (1) <0x708> [1] 00
#2: (1) <0x709> [1] 00
#3: (1) <0x703> [1] 00
#4: (0) <0x706> [0]
#5: (0) <0x500> [1] 01
#6: (0) <0x400> [1] 01
#7: (0) <0x100> [1] 01
#8: (0) <0x200> [1] 01
#9: (0) <0x000> [1] 08
#10: (24) <0x220> [124] 00 00 82 00 00 00 01 08 01 00 00 00 f0 84 04 08 
00 af 04 08 c0 68 91 bf 00 00 00 00 00 00 00 00 c0 06 60 b7 18 68 91 bf 
78 69 91 bf 80 0d 7c b7 ce 68 91 bf c0 68 91 bf 00 9b 04 08 60 69 91 bf 
78 69 91 bf cf 8e 04 08 00 af 04 08 c0 68 91 bf 00 00 00 00 00 00 00 00 
00 00 00 00 68 00 0f c1 e0 b8 7a b7 00 00 00 00 01 00 00 00 30 ae 10 f7 
04 5e 60 b7 e0 68 91 bf b0 68 91 bf
#11: (24) <0x220> [124] 00 00 05 07 00 00 01 07 01 00 00 00 f0 84 04 08 
00 af 04 08 c0 68 91 bf 00 00 00 00 00 00 00 00 c0 06 60 b7 18 68 91 bf 
78 69 91 bf 80 0d 7c b7 ce 68 91 bf c0 68 91 bf 00 9b 04 08 60 69 91 bf 
78 69 91 bf cf 8e 04 08 00 af 04 08 c0 68 91 bf 00 00 00 00 00 00 00 00 
00 00 00 00 68 00 0f c1 e0 b8 7a b7 00 00 00 00 01 00 00 00 30 ae 10 f7 
04 5e 60 b7 e0 68 91 bf b0 68 91 bf
#12: (32) <0x000> [50] 05 05 07 00 00 01 07 00 01 00 00 00 f0 84 04 08 
00 af 04 08 c0 68 91 bf 00 00 00 00 00 00 00 00 c0 06 60 b7 18 68 91 bf 
78 69 91 bf 80 0d 7c b7 ce 68
#13: (9) <0x100> [7] 05 07 00 00 01 07 00
#14: (0) <0x100> [0]
#15: (1) <0x705> [7] 00 00 01 01 00 09 07

None of this makes sense to me.


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