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Subject[PATCH 3.12 093/122] [media] media/rc: Send sync space information on the lirc device
From: Austin Lund <>

3.12-stable review patch. If anyone has any objections, please let me know.


commit a8f29e89f2b54fbf2c52be341f149bc195b63a8b upstream.

Userspace expects to see a long space before the first pulse is sent on
the lirc device. Currently, if a long time has passed and a new packet
is started, the lirc codec just returns and doesn't send anything. This
makes lircd ignore many perfectly valid signals unless they are sent in
quick sucession. When a reset event is delivered, we cannot know
anything about the duration of the space. But it should be safe to
assume it has been a long time and we just set the duration to maximum.

Signed-off-by: Austin Lund <>
Signed-off-by: Mauro Carvalho Chehab <>
Signed-off-by: Jiri Slaby <>
drivers/media/rc/ir-lirc-codec.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/media/rc/ir-lirc-codec.c b/drivers/media/rc/ir-lirc-codec.c
index ed2c8a1ed8ca..98893a8332c7 100644
--- a/drivers/media/rc/ir-lirc-codec.c
+++ b/drivers/media/rc/ir-lirc-codec.c
@@ -42,11 +42,17 @@ static int ir_lirc_decode(struct rc_dev *dev, struct ir_raw_event ev)
return -EINVAL;

/* Packet start */
- if (ev.reset)
- return 0;
+ if (ev.reset) {
+ /* Userspace expects a long space event before the start of
+ * the signal to use as a sync. This may be done with repeat
+ * packets and normal samples. But if a reset has been sent
+ * then we assume that a long time has passed, so we send a
+ * space with the maximum time value. */
+ IR_dprintk(2, "delivering reset sync space to lirc_dev\n");

/* Carrier reports */
- if (ev.carrier_report) {
+ } else if (ev.carrier_report) {
sample = LIRC_FREQUENCY(ev.carrier);
IR_dprintk(2, "carrier report (freq: %d)\n", sample);


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