Re: [RTnet-users] RTnet on Beaglebone Black

[Hidde V. (E2M) <hve...@e2...>]

On Mon, Jun 30, 2014 at 6:35 PM, Gilles Chanteperdrix
<gil...@xe...> wrote:
> On 06/30/2014 06:24 PM, Hidde Verstoep (E2M) wrote:
>> Hello,
>>
>> I'm trying to get RTnet to work on the Beaglebone Black (BBB).
>> However, I have come to a point where I don't know how to proceed. I
>> think here is a good place to ask the questions I have.
>>
>> Installing Xenomai was quite simple using this tutorial:
>> http://brunosmartins.info/xenomai-on-the-beaglebone-black-in-14-easy-steps/.
>> I only deviated from these steps to ensure I compiled the the network
>> driver components as modules.
>>
>> There are three modules for the network driver (as far as I can tell).
>> Loading the non-RTnet modules goes as follows:
>> $ modprobe smsc
>> $ modprobe davinci_mdio
>> $ modprobe ti_cpsw
>> Insert the network cable, and after a while the link comes up and
>> everything works fine. See dmesg output in the attached file
>> ticpsw.log.
>>
>> My ported version for the modules (as well as the r8169 driver I
>> ported earlier) can be found here:
>> https://github.com/hiddeate2m/rtnet/tree/master/. This is the entire
>> RTnet source tree. The specific modules can be found in
>> drivers/rt_smsc.c, drivers/rt_davinci_mdio.c and drivers/ticps/. The
>> modules can be build and installed as usual.
>>
>> Loading the modules ported to RTnet is similar:
>> $ insmod modules/rtnet.ko
>> $ insmod modules/rt_smsc.ko
>> $ insmod modules/rt_davinci_mdio.ko
>> $ insmod modules/rt_ticpsw.ko
>> $ ./sbin/rtifconfig rteth0 up
>> Insert the network cable. When the link comes up after a while the BBB
>> freezes completely. All the dmesg output I managed to capture can be
>> found in the attached file rt_ticpsw.log.
>>
>> One important difference between the logs is of course the WARNING
>> from ipipe.c. I searched the file, but could not find out if this is
>> important or not. Does anyone know?
>
> The warning comes from the fact that you are running an SMP kernel on a
> machine with only one processor. You can avoid it by compiling without
> CONFIG_SMP. Another advantage of disabling CONFIG_SMP is that you will
> gain better performances.
>
> --
>                                                                 Gilles.

Thanks Gilles. Disabling CONFIG_SMP did indeed remove the warning. It
also approximately halved the worst case latency. Unfortunately it did
not change the behaviour of the ported network driver. The attached
logs are now almost identical. Do you (or anyone else) have any tips
on how to debug this issue? I would like to have a trace from the
point where the BBB freezes. However, I don't know how I could get
something like that. Are there any (Xenomai specific?) resources
available that could help me debug this issue further?

Hidde