On 10/07/2015 04:25 PM, PRADHAN, MAKARAND (RC-CA) wrote: > Hi All, > > On further experimentation, I still feel that rt_intr_enable may be causing > my user space int handler to jump into secondary domain. >
rt_intr_enable() is a secondary domain call, it cannot execute over the primary domain simply because the infrastructure shared with the regular kernel that might be involved to enable/disable IRQs requires this. The nucleus forcibly relaxes the calling thread for this reason. So the behavior you observe is not a bug, it is actually the intent and requirement for carrying out such request. Check ksrc/native/syscall.c:4152, this call is tagged as "lostage", meaning that it shall run from the lowest pipeline domain stage, i.e. linux. This is the reason why handling interrupt top-halves in userland is a bad idea, and also the reason why the RT_INTR support has completely disappeared from 3.x's Alchemy API (formerly know as 2.x's "native" API), in favor of a UIO-like model called UDD, standing for "user-space device driver". There, top-halves must live in kernel space, and bottom-halves may live in userland, which is the only sane and safe way to handle interrupts from the latter. The rationale for this change is stated here: http://xenomai.org/migrating-from-xenomai-2-x-to-3-x/#irqhandling -- Philippe. _______________________________________________ Xenomai mailing list Xenomai@xenomai.org http://xenomai.org/mailman/listinfo/xenomai
