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Commit fee77829 authored by Steve Longerbeam's avatar Steve Longerbeam Committed by Philipp Zabel
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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: default avatarSteve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
parent 4791bd7d

drivers/gpu/ipu-v3/ipu-image-convert.c

+9 −0
Original line number Diff line number Diff line
@@ -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;