Commit b54a5c2d authored Jul 22, 2017 by Steve Longerbeam Committed by Mauro Carvalho Chehab Aug 08, 2017

media: imx: prpencvf: enable double write reduction

For the write channels with 4:2:0 subsampled YUV formats, avoid chroma
overdraw by only writing chroma for even lines. Reduces necessary write
memory bandwidth by at least 25% (more with rotation enabled).

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

parent 4560cb4a

drivers/staging/media/imx/imx-ic-prpencvf.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -374,6 +374,17 @@ static int prp_setup_channel(struct prp_priv *priv,
		image.phys0 = addr0;
		image.phys1 = addr1;

		if (channel == priv->out_ch \|\| channel == priv->rot_out_ch) {
		switch (image.pix.pixelformat) {
		case V4L2_PIX_FMT_YUV420:
		case V4L2_PIX_FMT_YVU420:
		case V4L2_PIX_FMT_NV12:
		/* Skip writing U and V components to odd rows */
		ipu_cpmem_skip_odd_chroma_rows(channel);
		break;
		}
		}

		ret = ipu_cpmem_set_image(channel, &image);
		if (ret)
		return ret;