>> >> I managed to compile and bring-up Xenomai v3.0.5, Ipipe v2, Linux >> v4.9.35 on a Wandboard Quad C1 [1]. I ran all unit-tests sucessfully >> [2] and was able to get RTnet ping to an external PC working. RT ping >> stops working after about 1000 pings... but that's a different story, >> I guess. >> >> So when I try to get a simple UDP server [3] running on top of RTnet I >> get "Unhandled fault: page domain fault (0x01b)" oopses, where the >> stacktrace indicates it has to do with rtudp.ko, e.g. >> rt_udp_recvmsg+03c/0x38c. Further googling [4] told me that these >> faults are related to missing copy_from_user() calls in the udp >> driver, which seems to have been enforced in the most recent kernel >> versions (after 4.1.x?). So if I go into the rtudp.ko source code and >> start introducing copy_to_user() statements, the the page domain >> faults go away one after the other...
I got the 4.1.x kernel running with the latest Ipipe/Xenomai patch and this solves the issue I was seeing with the 4.9.x kernel: The UDP server works now on top of the unpatched RTnet and I can communicate with it through rteth0 (rt_fec.ko) from a remote computer. So, something must have changed between 4.1.x (also potentially 4.4.x) and 4.9.x in terms of syscall interface. I'll also experiment to get the 4.4.x kernel running... W/r failing ping tests after 1000 rtpings: I think that's related to too few rtskbufs. Recently, I increased the rtskbuf pool to 256 (cat /proc/rtnet/rtskb). With this the rtpings keep on working beyond the 1000 rtping mark. It is interesting tough that I didn't get any kernel warning or error messages, which would tell me that I actually ran out of rtskbufs - ping just silently stopped working... >> >> At my company I basically want to propose to upgrade our current >> kernel (3.0.35) with a more recent one. So I'm looking for a hint >> what's the best+latest+supported kernel version for i.MX6 in a >> production grade setup, which can be patched with Xenomai3 (incl. >> RTnet)? >> > > I've been working on i.MX6 (4/2/1) + Xenomai 3.x for the last couple of > years over kernels 3.18, 4.1 and 4.4, for production grade software: so > far so good, provided one picks the latest I-pipe patches available. > > Although Xenomai 3 over kernel 4.9/arm is a bit younger, I have been > using this combo recently on i.MX6 for (Xenomai) development purposes > successfully, so far. > > I don't think that preferring any of the kernel releases mentioned above > among others should have a visible impact on RTnet user-wise. I only > tried with kernel 4.9 though. > Thanks Philippe. As said further above, I'll try Xenomai/RTnet on top of 4.4.x as well and see if that works for me... _______________________________________________ Xenomai mailing list [email protected] https://xenomai.org/mailman/listinfo/xenomai
