[media] rc: fix ghost keypresses with certain hw

With hardware that has to use ir_raw_event_store_edge to collect IR
sample durations, we were not doing an event reset unless
IR_MAX_DURATION had passed. That's around 4 seconds. So if someone
presses up, then down, with less than 4 seconds in between, they'd get
the initial up, then up and down upon pressing down.

To fix this, I've lowered the "send a reset event" logic's threshold to
the input device's REP_DELAY (defaults to 500ms), and with an
saa7134-based GPIO-driven IR receiver in a Hauppauge HVR-1150, I get
*much* better behavior out of the remote now. Special thanks to Devin
for providing the hardware to investigate this issue.

CC: [email protected]
CC: Devin Heitmueller <[email protected]>
Signed-off-by: Jarod Wilson <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>

drivers/media/rc/ir-raw.c

@@ -114,18 +114,20 @@ int ir_raw_event_store_edge(struct rc_dev *dev, enum raw_event_type type)
 	s64			delta; /* ns */
 	DEFINE_IR_RAW_EVENT(ev);
 	int			rc = 0;
+	int			delay;
 
 	if (!dev->raw)
 		return -EINVAL;
 
 	now = ktime_get();
 	delta = ktime_to_ns(ktime_sub(now, dev->raw->last_event));
+	delay = MS_TO_NS(dev->input_dev->rep[REP_DELAY]);
 
 	/* Check for a long duration since last event or if we're
 	 * being called for the first time, note that delta can't
 	 * possibly be negative.
 	 */
-	if (delta > IR_MAX_DURATION || !dev->raw->last_type)
+	if (delta > delay || !dev->raw->last_type)
 		type |= IR_START_EVENT;
 	else
 		ev.duration = delta;