2011-02-17 23:55:48 SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98236
Probably this belongs on a socketcan list, but I thought I'd start here.
I'm using socketcan on a custom BF537 board with 2010R1 (2.6.34.7-ADI-2010R1-pre-svn9156) (using the built-in 537 CAN peripheral). My application has been working fine (receiving all the packets I expect), but today I happened to type ifconfig and I noticed fully 1/2 of the packets being received are error frames. This was surprising because the Kvaser CAN analyzer I have on the bus isn't reporting any errors at all. My packet rate is pretty low - around 25 frames/s on a 500Kbit bus.
Exploring a little more, if I look at the bus transcript from my CAN analyzer I see something like:
0 00000020 8 1B 00 07 98 80 09 88 80 515.903420 R
0 00000020 8 1B 08 0B 78 80 09 78 80 515.903610 R
0 00000020 8 1B 10 07 88 80 08 78 80 515.903870 R
0 00000020 8 1B 14 07 C8 81 07 58 80 515.904120 R
0 00000020 8 1B 04 0B 98 80 08 88 80 515.904380 R
0 00000020 8 1B 0C 07 98 80 09 58 80 515.904570 R
0 00000060 6 6B 2B 00 00 00 00 515.911100 R
0 00000020 8 1F 00 08 98 80 09 88 80 516.153400 R
0 00000020 8 1F 08 0B 78 80 09 78 80 516.153660 R
0 00000020 8 1F 10 07 78 80 08 78 80 516.153910 R
0 00000020 8 1F 14 07 D8 81 07 58 80 516.154170 R
0 00000020 8 1F 04 0A 98 80 07 88 80 516.154360 R
0 00000020 8 1F 0C 07 98 80 09 68 80 516.154620 R
But if I run candump can0 -m 0 -e 0xffffffff on my host I get:
can0 20 [8] 1B 00 07 98 80 09 88 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1B 08 0B 78 80 09 78 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1B 10 07 88 80 08 78 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1B 14 07 C8 81 07 58 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1B 04 0B 98 80 08 88 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1B 0C 07 98 80 09 58 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 60 [6] 6B 2B 00 00 00 00
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1F 00 08 98 80 09 88 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1F 08 0B 78 80 09 78 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1F 10 07 78 80 08 78 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1F 14 07 D8 81 07 58 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1F 04 0A 98 80 07 88 80
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 20 [8] 1F 0C 07 98 80 09 68 80
I've no idea where those error frames are coming from. My bus is properly terminated (at both ends) and is very short in this case - just three nodes (+ the analyzer), separated from one another by ~1ft of twisted-pair. The only configuration I do is when I start up the interface in /etc/rc:
ip link set can0 type can bitrate 500000
ifconfig can0 up
I assume the detailed bit timing is being set to some default values by the driver... I wonder if that could be my problem.
Has anyone else seen this type of problem?
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2011-02-21 12:19:51 Re: SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98302
Small update on this. Turns out I get the ERRORFRAME frame BEFORE each good frame. One of the SocketCAN developers seems to think it's an ADI-specific problem. Can someone with a 537 eval board try this out and see if they're seeing the same problem?
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2011-02-21 12:24:53 Re: SocketCAN problem - ERRORFRAME
Mike Frysinger (UNITED STATES)
Message: 98303
i wonder if you took the bf537-stamp, installed the can loopback between the two ports on it, and then did some simple packet transmissions if you saw the same thing
could you post some code that does a simple socket creation + transmit that shows the same issue ?
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2011-02-21 13:04:05 Re: SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98304
This problem doesn't depend on my code at all... I'm just using the candump utility that builds with the distro.
Sure I can dig out my eval board and try it on there (may take some time to get the cabling working since I've never used CAN on it), but maybe someone already has one of these set up on their bench and could see if this is happening in a few minutes.
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2011-02-21 13:18:01 Re: SocketCAN problem - ERRORFRAME
Mike Frysinger (UNITED STATES)
Message: 98307
i'm not saying the problem is your code. i'm saying i'd like a series of steps that shows the problem on your side which i can then also do on my side. not much point in me slapping together some code only to have it work on my side.
so if you can show the issue using userspace utilities too, that's fine.
all bf537-stamp's should ship with a small loopback can connector ...
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2011-03-02 18:20:19 Re: SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98602
My previous posts were pretty clear about how this could be repeated using just the utilites that are part of the uClinux distro (no slapping together of code needed), but I spent the time to demonstrate the problem on an ADI board using the latest code anyway.
I just loaded the latest 2010R1-RC4 onto my B537 STAMP board (v2.1) and it shows exactly the same problem I'm seeing on my custom BF537 board. If I do candump can0 -m 0 -e 0xffffffff and send two '0 1 2 3' frames to CAN ID 0 (I'm generating these using my Kvaser Leaf CAN interface as I only have one BF537 STAMP board) I see the following on my board:
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 0 [4] 00 01 02 03
can0 20000004 [8] 00 01 00 00 00 00 00 00 ERRORFRAME
can0 0 [4] 00 01 02 03
That's an errorframe generated before each valid frame. ifconfig similary shows that half the receive frames are error frames.
I'll open a tracker for this issue.
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2011-03-02 18:23:05 Re: SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98603
Typo in my previous message... I'm actually running 2010R1-RC5 - it's the latest version off the download site.
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2011-03-02 21:48:10 Re: SocketCAN problem - ERRORFRAME
Mike Frysinger (UNITED STATES)
Message: 98609
you didnt show any commands for transmitting packets. you only showed sniffing the bus (candump). sniffing the bus isnt useful if no packets are being sent out.
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2011-03-02 23:06:53 Re: SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98612
I think you guys can figure out how to generate packets (using another board or whatever)... I listed the contents/addressses of the packets. It doesn't seem to matter what's in the packets - this error happens on every one. I'm sure cangen will work just fine.
- Jay
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2011-03-02 23:19:56 Re: SocketCAN problem - ERRORFRAME
Mike Frysinger (UNITED STATES)
Message: 98613
someone is going to half to, but ive never done socketcan before. without a test util to run on my own board to exhibit the issue, i'll just let someone else on our team get to it.
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2011-03-03 11:52:36 Re: SocketCAN problem - ERRORFRAME
Jay Ku (UNITED STATES)
Message: 98629
Just now I hooked two boards together (not both STAMPS but both BF537-based) and ran 'cangen can0' on one board and 'candump can0 -m 0 -e 0xffffffff' on the other and I see the errorframe before each correct frame. However, if I run cangen and candump on the same board, candump prints out the frames cangen is generating but there are no errors. So it seems it takes two boards to generate the error (and you have to be explicitly looking for errors like with the -e flag on candump - just 'candump can0' by default doesn't seem to print errors).
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2011-03-21 23:35:26 Re: SocketCAN problem - ERRORFRAME
steven miao (CHINA)
Message: 99111
Hi Jay,
I tested the socketcan with 2 bf537-stamp board, ran cangen on one board and
candump on the other board, but didn't see the error frame messages. Can you check the hardware
connection of you can line?
Linux version 2.6.34.7-ADI-2010R1-svn9517
root:/> ip link set can0 type can bitrate 500000
bfin_can bfin_can.0: setting CLOCK=0x0031 TIMING=0x0002
root:/> ifconfig can0 up
root:/> candump can0 -m 0 -e 0xffffffff
can0 567 [6] 69 98 3C 64 73 48
can0 451 [8] 4A 94 E8 2A EC 58 55 62
can0 729 [8] BA 58 1B 3D AB D7 7E 50
can0 1F2 [8] E3 A9 E2 79 46 E1 45 75
can0 7C [2] 54 08
can0 31B [8] E7 CD 90 11 8D 43 EF 66
can0 776 [8] 2E F9 9C 10 63 72 ED 0D
can0 233 [8] C9 C4 A7 41 9A 07 68 6B
can0 366 [2] 0D 50
can0 231 [8] A3 30 71 25 5A D9 BB 62
can0 125 [8] 05 B1 3A 33 17 A3 1D 72
can0 58 [8] 5E 84 63 67 D4 A8 A2 75
can0 5AB [2] CD D0
can0 69B [4] 54 24 F3 71
can0 40E [2] 74 F8
can0 521 [8] DC 8D 7B 73 87 F0 EA 6C
can0 270 [8] 3E C8 06 30 A1 D4 4F 61
can0 241 [1] FC
can0 23E [1] 7E
can0 1EA [8] 6B D3 EA 51 96 77 51 2D
can0 78F [8] 5C 58 55 38 2A 4E A6 70
can0 2EC [0]
can0 232 [8] 3C 8D 6D 7A 54 8F 58 4B
can0 1EC [8] DB 7F 43 38 5C A4 44 76
can0 102 [8] FE 78 94 57 43 BB 9A 74
can0 FB [8] AA DE A1 79 3A C3 C6 75
can0 5FB [8] D1 ED 0E 52 E6 3F 4A 37
can0 5 [8] 7C B7 9B 64 94 C7 5A 27
can0 575 [8] BE 15 01 18 61 A8 5B 23
can0 489 [8] 5C AF B5 15 BB 26 12 74
can0 6A8 [8] 0F B6 6A 3F 95 40 57 61
can0 7B1 [8] F1 E4 9B 57 B3 50 0C 31
can0 605 [8] F7 0B A7 25 00 BF BA 1D
can0 4E9 [1] 3A
can0 7CA [8] CB 4A 01 15 D0 7F 5E 5F
can0 148 [7] 64 47 B9 06 BD 96 C2
can0 21F [3] 1E 3F 1E
can0 71C [8] 64 C5 D9 51 C5 FD 3E 61
can0 314 [3] 5A 3E 96
can0 15E [8] 79 D3 0F 3B 63 2F EB 68
can0 13B [0]
can0 211 [8] 09 11 EA 71 DC 59 0F 10
can0 AA [4] AC D9 6D 6F
can0 61B [0]
can0 633 [8] E3 0E DE 74 50 C5 EB 68
can0 648 [7] 15 C3 2A 4A 5C 01 EE
can0 7BB [8] 22 84 F1 43 19 01 EF 60
can0 4BA [8] 7D 30 DA 49 F5 A5 55 70
can0 70B [1] 1A
can0 77F [3] F8 5A C7
