Hi Jan,

Jan Kiszka wrote:
> Wolfgang Grandegger wrote:
> > you know, on the SJA1000 the bus error interrupt can result in high
> > error interrupt rates and even hang the system on slow processors. Just
> > unplugging the CAN cable can cause such interrupt flooding. This problem
> >
> > popped up again recently and Sebastian proposed:
> >> Last summer we had a discussion about the BEI issue on the
> >> socketcan-ML. Two additional handling policies popped up:
> >> 1. The interface could restart itself after an amount of BEIs, thus
> >>    taking responsibility from the user application.
> >> 2. The BEI could be completely disabled if no one is interested in
> >>    this ype of error frame.
> >
> > As 2. is also my preferred solution, I have implemented it. The only
> > downside is that you do not see the error counter increasing when
> > /proc/rtcan/devices is inspected. We also discussed 1., but
> > RT-Socket-CAN does not restart the CAN controller by purpose and just
> > stoppping it requires user intervention.
>
> And if there is someone listening, how is the flooding issue on cable
> unplug etc. solved by option 2?

Hm, maybe we could implement 1 additionally (but without automatical restart)?

>
> What about something like option 3: After the first error occurred that
> may mark the beginning of a flood, disable that error interrupt until
> the next stop/start cycle or the user has read the event?

IIRC, there is no possibility to detect a "normal" bus error (acknowledge) 
appearing during normal operation from the one occuring when the cable is 
plugged off. The best indication is a high number of consecutive BEIs.

-- 
Sebastian

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