For the write channels with 4:2:0 subsampled YUV formats, avoid chroma
overdraw by only writing chroma for even lines (skip odd chroma rows).
This reduces necessary write memory bandwidth by at least 25% (more
with rotation enabled).
Signed-off-by: Steve Longerbeam <slongerb...@gmail.com>
---
drivers/gpu/ipu-v3/ipu-image-convert.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/ipu-v3/ipu-image-convert.c
b/drivers/gpu/ipu-v3/ipu-image-convert.c
index 36e88434513a..3036e01d8d42 100644
--- a/drivers/gpu/ipu-v3/ipu-image-convert.c
+++ b/drivers/gpu/ipu-v3/ipu-image-convert.c
@@ -1279,6 +1279,15 @@ static void init_idmac_channel(struct
ipu_image_convert_ctx *ctx,
if (rot_mode)
ipu_cpmem_set_rotation(channel, rot_mode);
+ /*
+ * Skip writing U and V components to odd rows in the output
+ * channels for planar 4:2:0.
+ */
+ if ((channel == chan->out_chan ||
+ channel == chan->rotation_out_chan) &&
+ image->fmt->planar && image->fmt->uv_height_dec == 2)
+ ipu_cpmem_skip_odd_chroma_rows(channel);
+
if (channel == chan->rotation_in_chan ||
channel == chan->rotation_out_chan) {
burst_size = 8;
--
2.17.1
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