If the attached sensor reports faulty frames at stream start via
g_skip_frames callback, add a delay to avoid them before enabling
the CSI hardware. Especially for sensors with a bt.656 interface,
any shifts in the SAV/EAV sync codes will cause the CSI to lose
vert/horiz sync.
Signed-off-by: Steve Longerbeam <steve_longerb...@mentor.com>
---
drivers/staging/media/imx/imx-media-csi.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/staging/media/imx/imx-media-csi.c
b/drivers/staging/media/imx/imx-media-csi.c
index d9c3a3b..8597d7e 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -9,6 +9,7 @@
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
+#include <linux/delay.h>
#include <linux/gcd.h>
#include <linux/interrupt.h>
#include <linux/module.h>
@@ -591,6 +592,7 @@ static int csi_setup(struct csi_priv *priv)
static int csi_start(struct csi_priv *priv)
{
+ u32 bad_frames = 0;
int ret;
if (!priv->sensor) {
@@ -598,6 +600,25 @@ static int csi_start(struct csi_priv *priv)
return -EINVAL;
}
+ ret = v4l2_subdev_call(priv->sensor->sd, sensor,
+ g_skip_frames, &bad_frames);
+ if (!ret && bad_frames) {
+ struct v4l2_fract *fi = &priv->frame_interval;
+ u32 delay_usec;
+
+ /*
+ * This sensor has bad frames when it is turned on,
+ * add a delay to avoid them before enabling the CSI
+ * hardware. Especially for sensors with a bt.656 interface,
+ * any shifts in the SAV/EAV sync codes will cause the CSI
+ * to lose vert/horiz sync.
+ */
+ delay_usec = DIV_ROUND_UP_ULL(
+ (u64)USEC_PER_SEC * fi->numerator * bad_frames,
+ fi->denominator);
+ usleep_range(delay_usec, delay_usec + 1000);
+ }
+
if (priv->dest == IPU_CSI_DEST_IDMAC) {
ret = csi_idmac_start(priv);
if (ret)
--
2.7.4
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