Hi Wolfgang, On 21/06/18 11:10, Wolfgang Grandegger wrote: > Hello Joe, > > Am 21.06.2018 um 12:04 schrieb Joe Burmeister: >> Hi Wolfgang, >> >> On 21/06/18 10:30, Wolfgang Grandegger wrote: >> >> [...snip...] >>>>>> It's when the power is going on or off to the device. We have some >>>>>> contactors to some big power that probably introduces a fair amount of >>>>>> noise on connect/disconnect causing can errors. The device we are >>>>>> talking to gets power from the same circuit. Though it's fine once up, >>>>>> it is born and dies in a hell fire of noise. But CAN should be ok with that. >>>>> So you have a bus error storm when the device is switched on (and off). >>>>> I suspect that the problem is while initializing the CAN device. >>>>> >>>>> [...snip...] >>>> The device is designed for this harsh environment (not by us), though it >>>> too is still in development. >>>> CAN should be pretty fault tolerant and it's the c_can/d_can driver that >>>> has the issue. It's out of sync with it's chip's status. >>>> When I get time on the setup, I'll see if that interrupt change stops >>>> that happening. >>> I didn't say that it's your fault ;). I just want to understand what >>> could cause the problem! I don't think it's hardware, either. >> Hopefully I've now loaded you with the situation. > Yep. Cool. >> It's fairly rare to happen even in our unusually harsh environment, >> unless we really push it with unrealistically tight loop, so this >> definitely comes under crazy edge cases. ;-) > Your conditions are special... maybe that's why the problem did not show > up yet. We're sure of it. It only showed up now as we are soak testing to try and reproduce these rare bugs. >> I'm just waiting for my turn to try my interrupt idea on the hardware (I >> hogged it yesterday) and reading the datasheet. >> Even if that works, I'm still thinking it might be an idea to check for >> bus off in the send as a fall back with a "this should never happen" >> kind of warning. > BTW, what hardware (Board/CPU) are you using? It's a Beagle Bone Black, TI's AM335x. It's part of a stack of prototype boards we designed. > > Wolfgang. Joe -- To unsubscribe from this list: send the line "unsubscribe linux-can" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
