diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c index 2d008e0d116a..ea966fc67d28 100644 --- a/drivers/pps/pps.c +++ b/drivers/pps/pps.c @@ -41,6 +41,9 @@ static __poll_t pps_cdev_poll(struct file *file, poll_table *wait) poll_wait(file, &pps->queue, wait); + if (pps->last_fetched_ev == pps->last_ev) + return 0; + return EPOLLIN | EPOLLRDNORM; } @@ -186,9 +189,11 @@ static long pps_cdev_ioctl(struct file *file, if (err) return err; - /* Return the fetched timestamp */ + /* Return the fetched timestamp and save last fetched event */ spin_lock_irq(&pps->lock); + pps->last_fetched_ev = pps->last_ev; + fdata.info.assert_sequence = pps->assert_sequence; fdata.info.clear_sequence = pps->clear_sequence; fdata.info.assert_tu = pps->assert_tu; @@ -272,9 +277,11 @@ static long pps_cdev_compat_ioctl(struct file *file, if (err) return err; - /* Return the fetched timestamp */ + /* Return the fetched timestamp and save last fetched event */ spin_lock_irq(&pps->lock); + pps->last_fetched_ev = pps->last_ev; + compat.info.assert_sequence = pps->assert_sequence; compat.info.clear_sequence = pps->clear_sequence; compat.info.current_mode = pps->current_mode; diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h index c7abce28ed29..aab0aebb529e 100644 --- a/include/linux/pps_kernel.h +++ b/include/linux/pps_kernel.h @@ -52,6 +52,7 @@ struct pps_device { int current_mode; /* PPS mode at event time */ unsigned int last_ev; /* last PPS event id */ + unsigned int last_fetched_ev; /* last fetched PPS event id */ wait_queue_head_t queue; /* PPS event queue */ unsigned int id; /* PPS source unique ID */