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From: Holger Schurig <holgerschurig@gmail.com>
To: linux-can@vger.kernel.org
Subject: CAN question: how to trace frame errors?
Date: Fri, 12 Jun 2015 11:29:25 +0200	[thread overview]
Message-ID: <CAOpc7mFv6ePXqkCZxRkCOC+BuY-PC14nAopZyFpEKHvj5gN_tw@mail.gmail.com> (raw)

Hi people,

I have two i.MX6 based boards with built-in FLEXCAN. On both boards I
loaded can_raw.

When I now run "cangen can0 -g 0 -x" one one board, I get frame errors
on the others (no matter if I run candump on the receiving side).


root@left:~# ifconfig can0; ip -s link show can0
can0      Link encap:UNSPEC  HWaddr
00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:20249437 errors:6 dropped:0 overruns:0 frame:6
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:116445504 (111.0 MiB)  TX bytes:0 (0.0 B)
          Interrupt:142

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
    116445504  20249437 6       0       6       0
    TX: bytes  packets  errors  dropped carrier collsns
    0          0        0       0       0       0


In drivers/net/can/flexcan.c I activated all the netdev_dbg() calls,
to see if it is the flexcan IP inside the i.MX6 that gives me a bus
error. This is unfortunately not the case.

And now I'm at a loss to find out where the CAN frames errors might be
come from. I'm not fluent in the Linux networking layers, I even don't
yet know in which struct the frame and error counters reside.



PS: kernel is 3.18.14 with the patches to flexcan from 4.1-rc7 and
also the drivers/net/can patch "can: dev: Consolidate and unify state
change handling". However, I noticed this frame errors the first times
before I applied the patches.

Holger

             reply	other threads:[~2015-06-12  9:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-12  9:29 Holger Schurig [this message]
2015-06-12  9:34 ` CAN question: how to trace frame errors? Marc Kleine-Budde
2015-06-12 10:01   ` Holger Schurig
2015-06-12 12:33     ` Tom Evans
2015-06-12 14:24       ` Holger Schurig
2015-06-13 15:30         ` Tom Evans
2015-06-13 20:28           ` Holger Schurig
2015-06-14  2:42             ` Tom Evans
2015-06-22 12:17               ` Holger Schurig
2015-06-22 13:15                 ` Marc Kleine-Budde
2015-06-24 14:29                   ` Holger Schurig
2015-06-25  8:37                     ` Tom Evans

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