candump error flags

candump error flags

[Paul Lever]

I'm trying to use the candump -e and -d options to catch errors. I
know that frames are being dropped, as I can see missing packets in
known sequences, yet I never see anything printed from candump
indicating any errors or dropped packets. Is there additional steps
needed to get output from -e/-d options? This is on a Beaglebone Black
platform.
My cmd line is:
candump -t a -e -d -r 16000 can0 > /media/testdata.raw&

Regards
Paul

Re: candump error flags

[Andri Yngvason]

On Fri, Nov 07, 2014 at 09:57:41AM -0400, Paul Lever wrote:
> I'm trying to use the candump -e and -d options to catch errors. I
> know that frames are being dropped, as I can see missing packets in
> known sequences, yet I never see anything printed from candump
> indicating any errors or dropped packets. Is there additional steps
> needed to get output from -e/-d options? This is on a Beaglebone Black
> platform.
> My cmd line is:
> candump -t a -e -d -r 16000 can0 > /media/testdata.raw&
>

Hi Paul,

Error handling is different between platforms. On some platforms you need to
enable berr-reporting to get errors. Some platforms support a limited set of
errors (or even no errors at all?)

You can grep for "CAN_ERR" in the driver for your platform to find out which
errors are implemented.

--
Cheers,
Andri

Re: candump error flags

[Marc Kleine-Budde]

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On 11/07/2014 02:57 PM, Paul Lever wrote:
> I'm trying to use the candump -e and -d options to catch errors. I
> know that frames are being dropped, as I can see missing packets in
> known sequences, yet I never see anything printed from candump
> indicating any errors or dropped packets. Is there additional steps
> needed to get output from -e/-d options? This is on a Beaglebone Black
> platform.
> My cmd line is:
> candump -t a -e -d -r 16000 can0 > /media/testdata.raw&

Make sure you're running a recent new kernel (v3.15 or better) as a lot
of fixes went into the driver.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
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Re: candump error flags

[Oliver Hartkopp]

On 07.11.2014 15:30, Marc Kleine-Budde wrote:
> On 11/07/2014 02:57 PM, Paul Lever wrote:
>> I'm trying to use the candump -e and -d options to catch errors. I
>> know that frames are being dropped, as I can see missing packets in
>> known sequences, yet I never see anything printed from candump
>> indicating any errors or dropped packets. Is there additional steps
>> needed to get output from -e/-d options? This is on a Beaglebone Black
>> platform.
>> My cmd line is:
>> candump -t a -e -d -r 16000 can0 > /media/testdata.raw&
>
> Make sure you're running a recent new kernel (v3.15 or better) as a lot
> of fixes went into the driver.
>

E.g. the dropcount functionality emerged in Linux 2.6.33
So a Debian Squeeze with 2.6.32 won't make it here ...

Regards,
Oliver

ps. additionally "candump -r 16000 -l can0 &" would be better :-)

Re: candump error flags

[Paul Lever]

>> Make sure you're running a recent new kernel (v3.15 or better) as a lot
>> of fixes went into the driver.
>>
>
> E.g. the dropcount functionality emerged in Linux 2.6.33
> So a Debian Squeeze with 2.6.32 won't make it here ...
I am running the c_can driver with the updates to late June.

> ps. additionally "candump -r 16000 -l can0 &" would be better :-)
I need the timestamps.

With berr-reporting enabled I still don't see any messages generated
by the -e and -d options to candump. Looking at my received data I can
see that there are missing sequential packets.

Regards
Paul

Re: candump error flags

[Oliver Hartkopp]

On 11/08/2014 03:47 PM, Paul Lever wrote:
>>> Make sure you're running a recent new kernel (v3.15 or better) as a lot
>>> of fixes went into the driver.
>>>
>>
>> E.g. the dropcount functionality emerged in Linux 2.6.33
>> So a Debian Squeeze with 2.6.32 won't make it here ...
> I am running the c_can driver with the updates to late June.

Of which kernel version?
A 2.6.32.x with security and stable patches is still no 2.6.33+

>> ps. additionally "candump -r 16000 -l can0 &" would be better :-)
> I need the timestamps.

The logfile format contains a unix timestamp (usec resolution) for every CAN
frame (and error message).

> 
> With berr-reporting enabled I still don't see any messages generated
> by the -e and -d options to candump. Looking at my received data I can
> see that there are missing sequential packets.

I'll better wait for the kernel version until answering based on assumptions.

Regards,
Oliver

Re: candump error flags

[Paul Lever]

>>> ps. additionally "candump -r 16000 -l can0 &" would be better :-)
>> I need the timestamps.
>
> The logfile format contains a unix timestamp (usec resolution) for every CAN
> frame (and error message).
Correct if I use the -t option. I was just commenting on the
suggestion not to use the option. Not sure why it was suggested.


> I'll better wait for the kernel version until answering based on assumptions.
The kernel is
 Image Name:   Linux-3.12.9-00111-gcad6b9e
with an updated c_can driver.

Regards
Paul

Re: candump error flags

[Oliver Hartkopp]

On 11/08/2014 04:14 PM, Paul Lever wrote:
>>>> ps. additionally "candump -r 16000 -l can0 &" would be better :-)
>>> I need the timestamps.
>>
>> The logfile format contains a unix timestamp (usec resolution) for every CAN
>> frame (and error message).
> Correct if I use the -t option. I was just commenting on the
> suggestion not to use the option. Not sure why it was suggested.
> 

Hm. No.

The -l option creates a logfile with the current date/time in the current
directory. The '-L' option puts the logfile format to the stdout.
Both of them contain a timestamp for all CAN frames and error messages.

No need for '-t?' in these cases.

>> I'll better wait for the kernel version until answering based on assumptions.
> The kernel is
>  Image Name:   Linux-3.12.9-00111-gcad6b9e
> with an updated c_can driver.

In this case the -d option should work.
But just for the records: The -d option detects drops from the network layer
to the application which opened the socket (here: candump).

So it basically detects problems when your user space application is not fast
enough to read and handle the CAN frames. It does NOT detect whether the CAN
driver dropped any frames.

Regards,
Oliver

Re: candump error flags

[Paul Lever]

> In this case the -d option should work.
> But just for the records: The -d option detects drops from the network layer
> to the application which opened the socket (here: candump).
>
> So it basically detects problems when your user space application is not fast
> enough to read and handle the CAN frames. It does NOT detect whether the CAN
> driver dropped any frames.


Thanks for the info. Is there an easy way to detect driver level
packet drops or overruns?The CANBUS is at 250,000 bitrate.

Regards
Paul

Re: candump error flags

[Oliver Hartkopp]

On 11/08/2014 04:34 PM, Paul Lever wrote:

>> In this case the -d option should work.
>> But just for the records: The -d option detects drops from the network layer
>> to the application which opened the socket (here: candump).
>>
>> So it basically detects problems when your user space application is not fast
>> enough to read and handle the CAN frames. It does NOT detect whether the CAN
>> driver dropped any frames.
> 
> 
> Thanks for the info. Is there an easy way to detect driver level
> packet drops or overruns?The CANBUS is at 250,000 bitrate.

When the CAN driver supports it, there's a bit in the error message

	CAN_ERR_CRTL_RX_OVERFLOW

for that.

See:
http://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/include/uapi/linux/can/error.h?h=linux-3.17.y#n63

Looking for it in the tree:
http://lxr.free-electrons.com/ident?i=CAN_ERR_CRTL_RX_OVERFLOW


It is used in c_can_handle_lost_msg_obj()

http://lxr.free-electrons.com/source/drivers/net/can/c_can/c_can.c#L348

So it should also increase rx_errors and rx_over_errors.

I'm not familiar with c_can - but can you see these statistics increasing the
values in your setup?

ip -stats link show can0

should display them.

Regards,
Oliver

Re: candump error flags

[Marc Kleine-Budde]

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On 11/08/2014 04:14 PM, Paul Lever wrote:
>>>> ps. additionally "candump -r 16000 -l can0 &" would be better :-)
>>> I need the timestamps.
>>
>> The logfile format contains a unix timestamp (usec resolution) for every CAN
>> frame (and error message).
> Correct if I use the -t option. I was just commenting on the
> suggestion not to use the option. Not sure why it was suggested.
> 
> 
>> I'll better wait for the kernel version until answering based on assumptions.
> The kernel is
>  Image Name:   Linux-3.12.9-00111-gcad6b9e

As I said, make sue you use at least v3.15.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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Re: candump error flags

[Paul Lever]

> I'm not familiar with c_can - but can you see these statistics increasing the
> values in your setup?
>
> ip -stats link show can0
>
> should display them.
Yes, they are shown in the stats:
ip -stats link show can0
3: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state
UNKNOWN mode DEFAULT group default qlen 10
    link/can
    RX: bytes  packets  errors  dropped overrun mcast
    619176     77397    71192   37270   0       0
    TX: bytes  packets  errors  dropped carrier collsns
    0          0        0       0       0       0

I'm just not seeing any from the candump listing.

Thanks again for the info
Paul

Re: candump error flags

[Paul Lever]

> As I said, make sue you use at least v3.15.
Understood. At this time I'm stuck with the release I'm using,
although I can update CAN drivers, etc. I won't be able to migrate to
a latter OS build for a few months.

Regards
Paul

Re: candump error flags

[Marc Kleine-Budde]

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On 11/09/2014 03:52 PM, Paul Lever wrote:
>> As I said, make sue you use at least v3.15.
> Understood. At this time I'm stuck with the release I'm using,
> although I can update CAN drivers, etc. I won't be able to migrate to
> a latter OS build for a few months.

There are more than 50 patches between v3.12 and current net/master on
the c_can driver.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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Re: candump error flags

[Paul Lever]

> There are more than 50 patches between v3.12 and current net/master on
> the c_can driver.
Yes. I updated to the major c_can driver re-write patches (I think
those were in April)  through June this year. If I need to I'll update
the c_can driver to the latest.

Regards
Paul

RE: candump error flags

[Pankajkumar Misra (RBEI/EEA2)]

Hi,

Are there any patches available for MCP251x module.
I am using it on Olimex board with spi interface.

I am getting bus-off very often & also not able to set any other baud rate than 250KBPS.

Best Regards,
Pankaj

-----Original Message-----
From: linux-can-owner@vger.kernel.org [mailto:linux-can-owner@vger.kernel.org] On Behalf Of Paul Lever
Sent: 09 नवम्बर 2014 20:53
To: Marc Kleine-Budde
Cc: Oliver Hartkopp; linux-can@vger.kernel.org
Subject: Re: candump error flags

> There are more than 50 patches between v3.12 and current net/master on
> the c_can driver.
Yes. I updated to the major c_can driver re-write patches (I think
those were in April)  through June this year. If I need to I'll update
the c_can driver to the latest.

Regards
Paul
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mcp251x (was: Re: candump error flags)

[Marc Kleine-Budde]

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Hey Pankajkumar,

please start a new thread, when starting a new topic.

On 11/10/2014 06:29 AM, Pankajkumar Misra (RBEI/EEA2) wrote:
> Are there any patches available for MCP251x module.
> I am using it on Olimex board with spi interface.

Any patched compared to which Kernel version?

> I am getting bus-off very often & also not able to set any other baud
> rate than 250KBPS.

Which driver are you using? The mcp251x chips are not the best CAN chips
to be used on a Linux based system.

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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