On 10/13/2010 11:39 AM, Alexander Stein wrote: >> I'm following the discussion and realized that it will not work for >> devices doing the local loopback in hardware, like the flexcan >> controller. Strictly speaking it will only work properly for drivers >> doing the local loopback in software when the TX done interrupt is >> handled. Also some USB devices are not able to do that properly.
> Thanks for the information so far. > I would need to get this info actually on flexcan hardware. What does it > actually mean in flexcan hardware? Does it receive it's own message like > normal ones? Or do they get discarded as they are known to be own messages? > Is there a way to detect if the hardware/driver allows local loopback? As Wolfgang pointed out, it doesn't work, i.e. they show up as "normal" messages. You cannot distinguish between loopback'ed messages and normal ones. But that can be fixed in the driver. I think we (the socketcan people) originally thought it's a better solution to loop the CAN frames back in hardware (if available), as it represents what's happening on the wire far better than software loopback. But it turns out that many people need the receive own messages feature (for whatever reason). Send patches or contact your favourite embedded linux support company :))) cheers, Marc -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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