From: Tobias Jakobi (Compleo) <tobias.jakobi.compleo@xxxxxxxxx> Sent: Thursday, March 7, 2024 12:07 PM > > Hello, > > I also noticed last year that RS485 was problematic on i.MX hardware. We > use a i.MX7 SoC located on a SoM by manufacturer Toradex. The SoM itself > is plugged into a proprietary board that features a Renesas ISL8xxx > RS485 transceiver. We talk ModBus RTU over the RS485 link. The SoC is > the ModBus master, the slave is a insulation monitoring device. > > Since we source the i.MX through Toradex, I opened a thread on their > community forum last year: > https://community.toradex.com/t/fixing-native-rs485-de-toggling-on-uart6/20573 > > I also realized very quickly that the newly introduced loopback logic > was the culprit. My solution currently consists of a new DT property > that effectively disables the toggling of the loopback mode: > https://gitlab.freedesktop.org/tobiasjakobi.compleo/linux-toradex/- > /commit/98397c9436f48a149e2da0b2969a2d1d2d88c611 > > Anyway, I have tested Christoph's patch and can confirm that the patch > (also) fixes the problems we are seeing. Test was done by applying the > patch to 6.1.80. I haven't tested Rickard's patch so far. > > Would be nice if this could later be backported to the 6.1.x kernel > (this is the kernel we currently use on our hardware). Rickard's patch in version 3 solved the same problem, so it should also fix the problem on your side. It has already been accepted and is already available in the next Kernel. It has a Fixes tag on it, so it should normally be backported to the 6.1.x Kernel soon. Regards Christo1ph
