gpu: ipu-v3: image-convert: 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 (skip odd chroma rows).
This reduces necessary write memory bandwidth by at least 25% (more
with rotation enabled).

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
This commit is contained in:
Steve Longerbeam 2019-06-13 18:02:55 -07:00 committed by Philipp Zabel
parent 4791bd7d6a
commit fee7782908

View file

@ -1280,6 +1280,15 @@ 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;