Hi everyone,

for about a month now, I have a problem with messages that get stalled,
causing the select system call on several CAN sockets to time out. We're
using the PEAK PCAN-USB interface on a Ubuntu 11.10 (kernel:
3.0.0-15-generic). I've been using the system for about 2 years now and
there were no revelant changes to the protocol or software lately. This
problem occurs quite frequently now.

What happens is, that our master sends out a message and receives 13
reply messages from 13 different nodes on the bus, at a frequency of
50Hz. This works for some time (minutes) and then a timeout on the
select system call occurs that reads from the 13 sockets. Wireshark
shows that there is an unusual time delay between the messages. They get
sent at the same time and are normally received within the time of
2-4ms. When the timeout occurs, this time is 30ms. When I turn on the
debug information in the peak driver I see debug output with time
stamps. On this layer the times are still ok when the timeout occurs.
Talking to the peak support, I got pointed at the socket can layer which
in this case might be causing the problem. However, I have no idea how
to debug this and find out more about the problem.

This part of the system is quite crucial, causing our robot controller
to fail. Time delays in the area of 30ms are extremely long. I don't see
why this would be happening and especially why it starts happening now.
Were there any changes to the socketcan layer and/or the kernel lately
that might be causing this?

thanks a lot
Cheers
Michael

-- 
Technische Universität München
Michael Jäntsch
Fakultät für Informatik
Robotics and Embedded Systems
Parkring 13
85748 Garching bei München
Tel: + 49.89.289.17626
Fax: + 49.89.289.17637
[email protected]
www6.in.tum.de


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