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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Steve Longerbeam <slongerbeam@gmail.com>,
	Fabio Estevam <festevam@gmail.com>,
	Tim Harvey <tharvey@gateworks.com>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
	Sasha Levin <sashal@kernel.org>,
	linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.4 35/50] media: imx-csi: Skip first few frames from a BT.656 source
Date: Sun,  4 Jul 2021 19:09:23 -0400	[thread overview]
Message-ID: <20210704230938.1490742-35-sashal@kernel.org> (raw)
In-Reply-To: <20210704230938.1490742-1-sashal@kernel.org>

From: Steve Longerbeam <slongerbeam@gmail.com>

[ Upstream commit e198be37e52551bb863d07d2edc535d0932a3c4f ]

Some BT.656 sensors (e.g. ADV718x) transmit frames with unstable BT.656
sync codes after initial power on. This confuses the imx CSI,resulting
in vertical and/or horizontal sync issues. Skip the first 20 frames
to avoid the unstable sync codes.

[fabio: fixed checkpatch warning and increased the frame skipping to 20]

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Tim Harvey <tharvey@gateworks.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/staging/media/imx/imx-media-csi.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index 367e39f5b382..40b7e60f4a47 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -753,9 +753,10 @@ static int csi_setup(struct csi_priv *priv)
 
 static int csi_start(struct csi_priv *priv)
 {
-	struct v4l2_fract *output_fi;
+	struct v4l2_fract *input_fi, *output_fi;
 	int ret;
 
+	input_fi = &priv->frame_interval[CSI_SINK_PAD];
 	output_fi = &priv->frame_interval[priv->active_output_pad];
 
 	/* start upstream */
@@ -764,6 +765,17 @@ static int csi_start(struct csi_priv *priv)
 	if (ret)
 		return ret;
 
+	/* Skip first few frames from a BT.656 source */
+	if (priv->upstream_ep.bus_type == V4L2_MBUS_BT656) {
+		u32 delay_usec, bad_frames = 20;
+
+		delay_usec = DIV_ROUND_UP_ULL((u64)USEC_PER_SEC *
+			input_fi->numerator * bad_frames,
+			input_fi->denominator);
+
+		usleep_range(delay_usec, delay_usec + 1000);
+	}
+
 	if (priv->dest == IPU_CSI_DEST_IDMAC) {
 		ret = csi_idmac_start(priv);
 		if (ret)
-- 
2.30.2


      parent reply	other threads:[~2021-07-04 23:10 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210704230938.1490742-1-sashal@kernel.org>
2021-07-04 23:09 ` [PATCH AUTOSEL 5.4 19/50] media: imx: imx7_mipi_csis: Fix logging of only error event counters Sasha Levin
2021-07-04 23:09 ` Sasha Levin [this message]

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