From 3cc506274a2f7c27fbd6a51d1177ea55bcccd980 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hans.verkuil@cisco.com>
Date: Sat, 18 Jun 2011 07:02:20 -0300
Subject: [PATCH] --- yaml --- r: 261403 b: refs/heads/master c:
 2151bdc887acfd6dc2c931b4d3c01f95e30b7df8 h: refs/heads/master i:   261401:
 dd821b849c10f34742e06f6878b1e61a418da68f   261399:
 235d8efe24398566d875b6412a11c78e1f281e0d v: v3

---
 [refs]                                 |  2 +-
 trunk/drivers/media/video/v4l2-event.c | 31 +++++++++++++++++++++++++-
 trunk/include/media/v4l2-event.h       |  6 +++++
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 06e9c2e9ec84..7e581453b1bf 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f1e393de382af9b9bd2462a42bfa16b8c501d81b
+refs/heads/master: 2151bdc887acfd6dc2c931b4d3c01f95e30b7df8
diff --git a/trunk/drivers/media/video/v4l2-event.c b/trunk/drivers/media/video/v4l2-event.c
index 9e325dd3ce27..b1c19fc2f08c 100644
--- a/trunk/drivers/media/video/v4l2-event.c
+++ b/trunk/drivers/media/video/v4l2-event.c
@@ -113,6 +113,7 @@ static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *e
 {
 	struct v4l2_subscribed_event *sev;
 	struct v4l2_kevent *kev;
+	bool copy_payload = true;
 
 	/* Are we subscribed? */
 	sev = v4l2_event_subscribed(fh, ev->type, ev->id);
@@ -130,12 +131,23 @@ static void __v4l2_event_queue_fh(struct v4l2_fh *fh, const struct v4l2_event *e
 		sev->in_use--;
 		sev->first = sev_pos(sev, 1);
 		fh->navailable--;
+		if (sev->elems == 1) {
+			if (sev->replace) {
+				sev->replace(&kev->event, ev);
+				copy_payload = false;
+			}
+		} else if (sev->merge) {
+			struct v4l2_kevent *second_oldest =
+				sev->events + sev_pos(sev, 0);
+			sev->merge(&kev->event, &second_oldest->event);
+		}
 	}
 
 	/* Take one and fill it. */
 	kev = sev->events + sev_pos(sev, sev->in_use);
 	kev->event.type = ev->type;
-	kev->event.u = ev->u;
+	if (copy_payload)
+		kev->event.u = ev->u;
 	kev->event.id = ev->id;
 	kev->event.timestamp = *ts;
 	kev->event.sequence = fh->sequence;
@@ -184,6 +196,19 @@ int v4l2_event_pending(struct v4l2_fh *fh)
 }
 EXPORT_SYMBOL_GPL(v4l2_event_pending);
 
+static void ctrls_replace(struct v4l2_event *old, const struct v4l2_event *new)
+{
+	u32 old_changes = old->u.ctrl.changes;
+
+	old->u.ctrl = new->u.ctrl;
+	old->u.ctrl.changes |= old_changes;
+}
+
+static void ctrls_merge(const struct v4l2_event *old, struct v4l2_event *new)
+{
+	new->u.ctrl.changes |= old->u.ctrl.changes;
+}
+
 int v4l2_event_subscribe(struct v4l2_fh *fh,
 			 struct v4l2_event_subscription *sub, unsigned elems)
 {
@@ -210,6 +235,10 @@ int v4l2_event_subscribe(struct v4l2_fh *fh,
 	sev->flags = sub->flags;
 	sev->fh = fh;
 	sev->elems = elems;
+	if (ctrl) {
+		sev->replace = ctrls_replace;
+		sev->merge = ctrls_merge;
+	}
 
 	spin_lock_irqsave(&fh->vdev->fh_lock, flags);
 	found_ev = v4l2_event_subscribed(fh, sub->type, sub->id);
diff --git a/trunk/include/media/v4l2-event.h b/trunk/include/media/v4l2-event.h
index 8d681e5ca552..6da793fa4d34 100644
--- a/trunk/include/media/v4l2-event.h
+++ b/trunk/include/media/v4l2-event.h
@@ -55,6 +55,12 @@ struct v4l2_subscribed_event {
 	struct v4l2_fh		*fh;
 	/* list node that hooks into the object's event list (if there is one) */
 	struct list_head	node;
+	/* Optional callback that can replace event 'old' with event 'new'. */
+	void			(*replace)(struct v4l2_event *old,
+					   const struct v4l2_event *new);
+	/* Optional callback that can merge event 'old' into event 'new'. */
+	void			(*merge)(const struct v4l2_event *old,
+					 struct v4l2_event *new);
 	/* the number of elements in the events array */
 	unsigned		elems;
 	/* the index of the events containing the oldest available event */