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From: Philipp Zabel
To: linux-media@vger.kernel.org
Cc: Steve Longerbeam ,
Hans Verkuil ,
Philipp Zabel
Subject: [PATCH v2] [media] imx: csi: enable double write reduction
Date: Wed, 19 Jul 2017 18:34:20 +0200
Message-Id: <20170719163420.27608-1-p.zabel@pengutronix.de>
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For 4:2:0 subsampled YUV formats, avoid chroma overdraw by only writing
chroma for even lines. Reduces necessary write memory bandwidth by 25%.
Signed-off-by: Philipp Zabel
Acked-by: Steve Longerbeam
---
Changes since v1:
- Move odd row skipping setup into existing switch statement.
---
drivers/staging/media/imx/imx-media-csi.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index a2d26693912ec..f2d64d1eeff80 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -357,6 +357,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv)
passthrough = (sensor_ep->bus_type != V4L2_MBUS_CSI2 &&
sensor_ep->bus.parallel.bus_width >= 16);
passthrough_bits = 16;
+ /* Skip writing U and V components to odd rows */
+ ipu_cpmem_skip_odd_chroma_rows(priv->idmac_ch);
break;
case V4L2_PIX_FMT_YUYV:
case V4L2_PIX_FMT_UYVY: