Hardlock when EdgeDetect is used

[jax-b]

I found a small issue with the library. For some reason when rpio is close and EdgeDetect is still enable it will hard lock the rpi. i tested it on both a pi3 and pi4. if i call pin.Detect(rpio.NoEdge) before close nothing locks up and everything is fine. I don't have any logs unfortunately dmsg and the kernel log give no insight.

go version: go1.17 linux/arm64 kernel version (uname-a): Linux XXXX 5.13.0-1013-raspi #15-Ubuntu SMP PREEMPT Fri Jan 7 23:16:57 UTC 2022 aarch64 aarch64 aarch64 GNU/Linux go-rpio version: 4.5.1

[yzj578492228]

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[jax-b]

I have updated to 4.6 and it is still a issue, I had one run where instead of crashing it locked the file system

[rspier]

I can replicate this on v4.6.0 on a Pi Zero W. It hangs if I run as my user (which is a member of group gpio) but works fine running as root.

[rspier]

Found

WARNING: this might make your Pi unresponsive, if this happens, you should either run the code as root, or add dtoverlay=gpio-no-irq to /boot/config.txt and restart your pi,

in the docs.

It came from https://github.com/stianeikeland/go-rpio/issues/35, of which this bug is likely a dupe.

[peritonow]

Thank you ... yes, adding 'dtoverlay=gpio-no-irq to /boot/config.txt' was the solution in my case due to linux kernel bug still present in version 5.10.103-v7+. Maybe it would be useful to add this as part of go-rpio documentation. this was useful : https://www.i-programmer.info/programming/hardware/14114-raspberry-pi-iot-in-c-events-a-interrupts.html?start=1. BTW, Linux doesn't support user-mode interrupts so it works only if run as root user in older Linux kernels.

it seems that in case of the hardlock prevention one can issue a code to disable gpio-no-irq per program run. The code is in C, but it can be easily adopted to golang.

... c code
int txfound = 0; while (fgets(output, sizeof (output), fp) != NULL) { printf("%s\n\r", output); fflush(stdout); if (strstr(output, "gpio-no-irq") != NULL) { txfound = 1; } } pclose(fp); if (txfound == 0) { fp = popen("sudo dtoverlay gpio-no-irq","r"); if (fp == NULL) { printf("Failed to run command\n\r"); exit(1); } pclose(fp); } ...