Date: Fri, 27 Nov 2020 19:45:32 -0300 From: "Dr. Rolf Jansen" <freebsd-rj@obsigna.com> To: Ian Lepore <ian@freebsd.org> Cc: freebsd-arm@freebsd.org Subject: Re: User Space GPIO Interrupt programming - GSoC-2018 Message-ID: <BD08359D-C61D-454F-95A1-92B248707B9C@obsigna.com> In-Reply-To: <1e6993d43d22d6ce1aa2860a61745356688d1e53.camel@freebsd.org> References: <2B01780F-D367-48A3-A827-B479030A496D@obsigna.com> <c55d7f332631b69c3241a60538a6a7b5475d93b9.camel@freebsd.org> <FBEF19B1-0504-4CDF-976C-C50707E06584@obsigna.com> <8d806302-479c-ca34-3fdb-96d27f40e212@viruzzz.org> <8655AF30-273B-48E7-98CD-007AA1D265F5@obsigna.com> <54ffe2d2-01a2-8b43-94fa-aee4a3f89861@viruzzz.org> <08649892ca2ab434c261d36e0e13ba051086de6f.camel@freebsd.org> <1e6993d43d22d6ce1aa2860a61745356688d1e53.camel@freebsd.org>
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Am 27.11.2020 um 15:04 schrieb Ian Lepore <ian@freebsd.org>: > On Fri, 2020-11-27 at 10:16 -0700, Ian Lepore wrote: >> 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. >>>=20 >>> 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. >>>=20 >>=20 >> Please don't top-post on freebsd mailing lists. >>=20 >> 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. >>=20 >> 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. >>=20 >=20 > The gsoc2018 code, with locking and style(9) fixes, is now at: >=20 > https://reviews.freebsd.org/D27398 I got it working, and as expected, by your comments the level interrupt = mode has been disabled. I am OK with this. Later, I will add more = comments on this in my response to you other e-mail. Best regards Rolf=
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