Hi, On Thu, Dec 10, 2020 at 11:07 PM Maulik Shah <mkshah@xxxxxxxxxxxxxx> wrote: > > I have slightly modified your test case (see at > https://crrev.com/c/2584729) which is as per what i used in my testing. > > Here is what i am doing, setting GPIO to a fixed function (function 2 here) > Note that function 0 is the GPIO (interrupt mode). > > 1) Pull up the GPIO in function 2 > 2) Pull down the GPIO in function 2 > > Repeat above steps, and you will see fake interrupt every time pull down/up. > This proves that if you mux away from GPIO then still PDC sees the line > and can latch the interrupt at GIC. Ah, super useful example! Thanks! Yes, I can replicate your results. ...but this seems to contradict my other test. Ah, dang, I think I see the problem with my original test. The important difference is that in your test you used the alternate function "mi2s_2" and in mine I used "qspi_data". When I selected "qspi_data" it must have been actively driving the pin and _that's_ why I couldn't affect it. When I change my test to use "mi2s_2" then my toggles via "wp enable" and "wp disable" cause phantom interrupts. That confirms what you're saying: the PDC _can_ see the twiddles even when muxed away. Presumably the active driving my "qspi_data" is also what caused my phantom glitches. So, as you said, that means my mental model is totally wrong here. Wow, if I had known that earlier I would have saved a lot of time. That'll learn me... OK, v4 being posted and you can see if that handles all the cases? -Doug
