media: rockchip: rga: Only set output CSC mode for RGB input

Setting the output CSC mode is required for a YUV output, but must not
be set when the input is also YUV. Doing this (as tested with a YUV420P
to YUV420P conversion) results in wrong colors.

Adapt the logic to only set the output CSC mode when the output is YUV and
the input is RGB. Also add a comment to clarify the rationale.

Fixes: f7e7b48e6d79 ("[media] rockchip/rga: v4l2 m2m support")
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/platform/rockchip/rga/rga-hw.c b/drivers/media/platform/rockchip/rga/rga-hw.c
index 5607ee8..aaa96f2 100644 (file)
--- a/drivers/media/platform/rockchip/rga/rga-hw.c
+++ b/drivers/media/platform/rockchip/rga/rga-hw.c
@@ -200,6 +200,11 @@ static void rga_cmd_set_trans_info(struct rga_ctx *ctx)
        dst_info.data.format = ctx->out.fmt->hw_format;
        dst_info.data.swap = ctx->out.fmt->color_swap;
 
+       /*
+        * CSC mode must only be set when the colorspace families differ between
+        * input and output. It must remain unset (zeroed) if both are the same.
+        */
+
        if (RGA_COLOR_FMT_IS_YUV(ctx->in.fmt->hw_format) &&
            RGA_COLOR_FMT_IS_RGB(ctx->out.fmt->hw_format)) {
                switch (ctx->in.colorspace) {
@@ -212,7 +217,8 @@ static void rga_cmd_set_trans_info(struct rga_ctx *ctx)
                }
        }
 
-       if (RGA_COLOR_FMT_IS_YUV(ctx->out.fmt->hw_format)) {
+       if (RGA_COLOR_FMT_IS_RGB(ctx->in.fmt->hw_format) &&
+           RGA_COLOR_FMT_IS_YUV(ctx->out.fmt->hw_format)) {
                switch (ctx->out.colorspace) {
                case V4L2_COLORSPACE_REC709:
                        dst_info.data.csc_mode = RGA_SRC_CSC_MODE_BT709_R0;