From 7e360fa0c0f3e7dd1aa8f2b574d7b461d0caf5e2 Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Wed, 11 Aug 2021 13:36:54 +0200
Subject: [PATCH] media: cec-pin: fix off-by-one SFT check
The CEC pin framework has to wait for the CEC bus to be idle for the
requested Signal Free Time before it can start a transmit.
However, the check for that was off by one, so transmits would start one
bit period (2.4ms) too late.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
drivers/media/cec/core/cec-pin.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/cec/core/cec-pin.c b/drivers/media/cec/core/cec-pin.c
index 8c613aa649c6..a60b6f03a6a1 100644
--- a/drivers/media/cec/core/cec-pin.c
+++ b/drivers/media/cec/core/cec-pin.c
@@ -957,7 +957,7 @@ static enum hrtimer_restart cec_pin_timer(struct hrtimer *timer)
* so we can kick off the pending transmit.
*/
delta = ktime_us_delta(ts, pin->ts);
- if (delta / CEC_TIM_DATA_BIT_TOTAL >
+ if (delta / CEC_TIM_DATA_BIT_TOTAL >=
pin->tx_signal_free_time) {
pin->tx_nacked = false;
if (tx_custom_start(pin))
@@ -968,7 +968,7 @@ static enum hrtimer_restart cec_pin_timer(struct hrtimer *timer)
cec_pin_low(pin);
break;
}
- if (delta / CEC_TIM_DATA_BIT_TOTAL >
+ if (delta / CEC_TIM_DATA_BIT_TOTAL >=
pin->tx_signal_free_time - 1)
pin->state = CEC_ST_TX_WAIT;
break;