[systemd-devel] sd_event_add_io with EPOLLPRI option

[Yong Li]

Hi all,

I want to use the sd_event_add_io API to monitor a GPIO pin status
change. This pin supports intrrupts(echo both > edge). And it works
using the epoll code at https://gist.github.com/jadonk/2587524: The
callback function will be called if there is data change on the pin.

However, the sd_event_add_io does not work: the callback will always
be triggered(without pin status change). I am using this example:
http://0pointer.net/blog/introducing-sd-event.html. Just replace the
fd = open("/sys/class/gpio/gpio34/value", O_RDWR | O_NONBLOCK); and
replace EPOLLIN using EPOLLPRI.

Any suggestions/comments?


Thanks,
Yong