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Diffstat (limited to 'drivers/media/v4l2-core/videobuf2-core.c')
-rw-r--r--drivers/media/v4l2-core/videobuf2-core.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 07ab0677e259..2eef5ef93e93 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -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;

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