laforge has uploaded this change for review. ( https://gerrit.osmocom.org/c/dahdi-linux/+/34011 )

Change subject: Flush DAHDI->trunkdev FIFO at open time ......................................................................

Flush DAHDI->trunkdev FIFO at open time

If we don't do this, we always have a full FIFO at the time userspace opens the trunkdev, adding latency for no good reason.

Change-Id: Ifbda3766309cc7d6be485073e36607bdd6742f3a --- M drivers/dahdi/trunkdev/frame_fifo.c M drivers/dahdi/trunkdev/frame_fifo.h M drivers/dahdi/trunkdev/trunkdev.c 3 files changed, 26 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/dahdi-linux refs/changes/11/34011/1

diff --git a/drivers/dahdi/trunkdev/frame_fifo.c b/drivers/dahdi/trunkdev/frame_fifo.c index 19b6dba..3b7732f 100644 --- a/drivers/dahdi/trunkdev/frame_fifo.c +++ b/drivers/dahdi/trunkdev/frame_fifo.c @@ -53,6 +53,15 @@ spin_lock_init(&fifo->lock); }

+/*! Flush (drop) the entire content of the FIFO */ +void frame_fifo_flush(struct frame_fifo *fifo) +{ + unsigned long flags; + spin_lock_irqsave(&fifo->lock, flags); + fifo->next_out = fifo->next_in; + spin_unlock_irqrestore(&fifo->lock, flags); +} + #define FIFO_BUF_END(f) ((f)->buf + sizeof((f)->buf))

/*! put one received frames into the FIFO. diff --git a/drivers/dahdi/trunkdev/frame_fifo.h b/drivers/dahdi/trunkdev/frame_fifo.h index af02811..b07cddc 100644 --- a/drivers/dahdi/trunkdev/frame_fifo.h +++ b/drivers/dahdi/trunkdev/frame_fifo.h @@ -20,6 +20,8 @@ void (*threshold_cb)(struct frame_fifo *fifo, unsigned int frames, void *priv), void *priv);

+void frame_fifo_flush(struct frame_fifo *fifo); + /* number of frames currently available in FIFO */ static inline unsigned int __frame_fifo_frames(struct frame_fifo *fifo) { diff --git a/drivers/dahdi/trunkdev/trunkdev.c b/drivers/dahdi/trunkdev/trunkdev.c index 8375c86..339b9d0 100644 --- a/drivers/dahdi/trunkdev/trunkdev.c +++ b/drivers/dahdi/trunkdev/trunkdev.c @@ -456,6 +456,9 @@ span->alarms &= ~(ALL_RY_ALARMS|DAHDI_ALARM_LOS); dahdi_alarm_notify(span); spin_unlock_irqrestore(&span->lock, flags); + /* FIFO should be full at this point, let's flush it as now we actually + * have a receiver */ + frame_fifo_flush(&td->to_trunk);

open.spanno = span->spanno; if (copy_to_user((__user void *) data, &open, sizeof(open)))