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Commit e35e41b5 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
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[media] vb2: reject output buffers with V4L2_FIELD_ALTERNATE 



This is not allowed by the spec and does in fact not make any sense.
Return -EINVAL if this is the case.

Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Acked-by: default avatarPawel Osciak <pawel@osciak.com>
Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
parent ebd7c505

drivers/media/v4l2-core/videobuf2-core.c

+13 −0
Original line number Diff line number Diff line
@@ -1564,6 +1564,19 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b) 
		dprintk(1, "plane parameters verification failed: %d\n", ret);

		return ret;

	}

	if (b->field == V4L2_FIELD_ALTERNATE && V4L2_TYPE_IS_OUTPUT(q->type)) {

		/*

		 * If the format's field is ALTERNATE, then the buffer's field

		 * should be either TOP or BOTTOM, not ALTERNATE since that

		 * makes no sense. The driver has to know whether the

		 * buffer represents a top or a bottom field in order to

		 * program any DMA correctly. Using ALTERNATE is wrong, since

		 * that just says that it is either a top or a bottom field,

		 * but not which of the two it is.

		 */

		dprintk(1, "the field is incorrectly set to ALTERNATE for an output buffer\n");

		return -EINVAL;

	}



	vb->state = VB2_BUF_STATE_PREPARING;

	vb->v4l2_buf.timestamp.tv_sec = 0;