As defined in the specification, the `controls` field in the configuration space is only valid/present if VIRTIO_SND_F_CTLS is negotiated. From https://docs.oasis-open.org/virtio/virtio/v1.3/virtio-v1.3.html: 5.14.4 Device Configuration Layout ... controls (driver-read-only) indicates a total number of all available control elements if VIRTIO_SND_F_CTLS has been negotiated. Let's use the same style used in virtio_blk.h to clarify this and to avoid confusion as happened in QEMU (see link). Link: https://gitlab.com/qemu-project/qemu/-/issues/2805 Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> --- include/uapi/linux/virtio_snd.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/virtio_snd.h b/include/uapi/linux/virtio_snd.h index 5f4100c2cf04..a4cfb9f6561a 100644 --- a/include/uapi/linux/virtio_snd.h +++ b/include/uapi/linux/virtio_snd.h @@ -25,7 +25,7 @@ struct virtio_snd_config { __le32 streams; /* # of available channel maps */ __le32 chmaps; - /* # of available control elements */ + /* # of available control elements (if VIRTIO_SND_F_CTLS) */ __le32 controls; }; -- 2.48.1
