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12c409aa1e
Because pps_cdev_poll() returns unconditionally EPOLLIN,
a user space program that calls select/poll get always an immediate data
ready-to-read response. As a result the intended use to wait until next
data becomes ready does not work.
User space snippet:
struct pollfd pollfd = {
.fd = open("/dev/pps0", O_RDONLY),
.events = POLLIN|POLLERR,
.revents = 0 };
while(1) {
poll(&pollfd, 1, 2000/*ms*/); // returns immediate, but should wait
if(revents & EPOLLIN) { // always true
struct pps_fdata fdata;
memset(&fdata, 0, sizeof(memdata));
ioctl(PPS_FETCH, &fdata); // currently fetches data at max speed
}
}
Lets remember the last fetch event counter and compare this value
in pps_cdev_poll() with most recent event counter
and return 0 if they are equal.
Signed-off-by: Denis OSTERLAND-HEIM <denis.osterland@diehl.com>
Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Fixes:
|
||
|---|---|---|
| .. | ||
| clients | ||
| generators | ||
| kapi.c | ||
| kc.c | ||
| kc.h | ||
| Kconfig | ||
| Makefile | ||
| pps.c | ||
| sysfs.c | ||