Hi Philipp,
This is the same as your patch to CSI, applied to ic-prpencvf.
I'm not really sure what this cpmem bit is doing. The U/V planes
in memory are already subsampled by 2 in both width and height.
This must be referring to what the IDMAC is transferring on the bus,
but why would it place duplicate U/V samples on the bus in the first
place?
Anyway, thanks for the heads-up on this.
Steve
On 07/22/2017 02:21 PM, Steve Longerbeam wrote:
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@xxxxxxxxxx>
---
drivers/staging/media/imx/imx-ic-prpencvf.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/staging/media/imx/imx-ic-prpencvf.c b/drivers/staging/media/imx/imx-ic-prpencvf.c
index ed363fe..42c5045 100644
--- a/drivers/staging/media/imx/imx-ic-prpencvf.c
+++ b/drivers/staging/media/imx/imx-ic-prpencvf.c
@@ -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;
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