This is a note to let you know that I've just added the patch titled
media: tegra-cec: reset rx_buf_cnt when start bit detected
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: media-tegra-cec-reset-rx_buf_cnt-when-start-bit-detected.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From e113d65ae417ae6d9be229649b81d404c47ade79 Mon Sep 17 00:00:00 2001
From: Hans Verkuil hverkuil@xs4all.nl Date: Wed, 28 Feb 2018 05:47:07 -0500 Subject: media: tegra-cec: reset rx_buf_cnt when start bit detected
From: Hans Verkuil hverkuil@xs4all.nl
commit e113d65ae417ae6d9be229649b81d404c47ade79 upstream.
If a start bit is detected, then reset the receive buffer counter to 0.
This ensures that no stale data is in the buffer if a message is broken off midstream due to e.g. a Low Drive condition and then retransmitted.
The only Rx interrupts we need to listen to are RX_REGISTER_FULL (i.e. a valid byte was received) and RX_START_BIT_DETECTED (i.e. a new message starts and we need to reset the counter).
Signed-off-by: Hans Verkuil hans.verkuil@cisco.com Cc: stable@vger.kernel.org # for v4.15 and up Signed-off-by: Mauro Carvalho Chehab mchehab@s-opensource.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/media/platform/tegra-cec/tegra_cec.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)
--- a/drivers/media/platform/tegra-cec/tegra_cec.c +++ b/drivers/media/platform/tegra-cec/tegra_cec.c @@ -172,16 +172,13 @@ static irqreturn_t tegra_cec_irq_handler } }
- if (status & (TEGRA_CEC_INT_STAT_RX_REGISTER_OVERRUN | - TEGRA_CEC_INT_STAT_RX_BUS_ANOMALY_DETECTED | - TEGRA_CEC_INT_STAT_RX_START_BIT_DETECTED | - TEGRA_CEC_INT_STAT_RX_BUS_ERROR_DETECTED)) { + if (status & TEGRA_CEC_INT_STAT_RX_START_BIT_DETECTED) { cec_write(cec, TEGRA_CEC_INT_STAT, - (TEGRA_CEC_INT_STAT_RX_REGISTER_OVERRUN | - TEGRA_CEC_INT_STAT_RX_BUS_ANOMALY_DETECTED | - TEGRA_CEC_INT_STAT_RX_START_BIT_DETECTED | - TEGRA_CEC_INT_STAT_RX_BUS_ERROR_DETECTED)); - } else if (status & TEGRA_CEC_INT_STAT_RX_REGISTER_FULL) { + TEGRA_CEC_INT_STAT_RX_START_BIT_DETECTED); + cec->rx_done = false; + cec->rx_buf_cnt = 0; + } + if (status & TEGRA_CEC_INT_STAT_RX_REGISTER_FULL) { u32 v;
cec_write(cec, TEGRA_CEC_INT_STAT, @@ -255,7 +252,7 @@ static int tegra_cec_adap_enable(struct TEGRA_CEC_INT_MASK_TX_BUS_ANOMALY_DETECTED | TEGRA_CEC_INT_MASK_TX_FRAME_TRANSMITTED | TEGRA_CEC_INT_MASK_RX_REGISTER_FULL | - TEGRA_CEC_INT_MASK_RX_REGISTER_OVERRUN); + TEGRA_CEC_INT_MASK_RX_START_BIT_DETECTED);
cec_write(cec, TEGRA_CEC_HW_CONTROL, TEGRA_CEC_HWCTRL_TX_RX_MODE); return 0;
Patches currently in stable-queue which might be from hverkuil@xs4all.nl are
queue-4.15/media-tegra-cec-reset-rx_buf_cnt-when-start-bit-detected.patch