Re: User Space GPIO Interrupt programming - GSoC-2018
Ian Lepore <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
On Fri, 2020-11-27 at 14:28 +0300, Vladimir Goncharov wrote: > Here it is. > There is struct gpioc_event with pin number and bintime which is send > to userspace. > > Also I'm thinking about to implementation notofication without extra > reading from socket via struct kevent's extra fields (fflags/ext[4]), > looks like it is possible. > Please don't top-post on freebsd mailing lists. I think we need a way for the app to choose whether it wants simple reporting of pin number (like the original code) perhaps along with a count, versus requesting detailed per-event data. I'm going to propose something more detailed about this as soon as I get my thoughts all organized. I also want to get the original code and the locking fixes I've done to it into a phab review for people to start looking at before starting to do new major changes to it. Allocating memory in the interrupt handler isn't a good idea, it will just increase latency on processing other pin interrupts and lead to inaccurate timestamps. IMO, it would be better to allocate a fixed array of events; when the app requests detailed event reporting it can request the number of stored events it wants handled and we could allocate all at once based on that. -- Ian _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-arm To unsubscribe, send any mail to "[email protected]"