media: rkvdec: Enable capture buffer holding for H264

In order to support interlaced video decoding, the driver must
allow holding the capture buffer so that the second field can
be decoded into it.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/staging/media/rkvdec/rkvdec.c

@@ -127,6 +127,7 @@ static const struct rkvdec_coded_fmt_desc rkvdec_coded_fmts[] = {
 		.ops = &rkvdec_h264_fmt_ops,
 		.num_decoded_fmts = ARRAY_SIZE(rkvdec_h264_vp9_decoded_fmts),
 		.decoded_fmts = rkvdec_h264_vp9_decoded_fmts,
+		.subsystem_flags = VB2_V4L2_FL_SUPPORTS_M2M_HOLD_CAPTURE_BUF,
 	},
 	{
 		.fourcc = V4L2_PIX_FMT_VP9_FRAME,
@@ -385,6 +386,9 @@ static int rkvdec_s_output_fmt(struct file *file, void *priv,
 	cap_fmt->fmt.pix_mp.ycbcr_enc = f->fmt.pix_mp.ycbcr_enc;
 	cap_fmt->fmt.pix_mp.quantization = f->fmt.pix_mp.quantization;
 
+	/* Enable format specific queue features */
+	vq->subsystem_flags |= desc->subsystem_flags;
+
 	return 0;
 }
 

drivers/staging/media/rkvdec/rkvdec.h

@@ -82,6 +82,7 @@ struct rkvdec_coded_fmt_desc {
 	const struct rkvdec_coded_fmt_ops *ops;
 	unsigned int num_decoded_fmts;
 	const u32 *decoded_fmts;
+	u32 subsystem_flags;
 };
 
 struct rkvdec_dev {