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2025-02-14virtio_snd.h: clarify that `controls` depends on VIRTIO_SND_F_CTLSStefano Garzarella
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@redhat.com> Acked-by: Eugenio Pérez <eperezma@redhat.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Link: https://patch.msgid.link/20250213161825.139952-1-sgarzare@redhat.com
2024-02-09ALSA: virtio: add support for audio controlsAnton Yakovlev
Implementation of support for audio controls in accordance with the extension of the virtio sound device specification [1] planned for virtio-v1.3-cs01. The device can announce the VIRTIO_SND_F_CTLS feature. If the feature is negotiated, then an additional field appears in the configuration space: struct virtio_snd_config { ... /* number of available control elements */ __le32 controls; }; The driver can send the following requests to manage audio controls: enum { ... /* control element request types */ VIRTIO_SND_R_CTL_INFO = 0x0300, VIRTIO_SND_R_CTL_ENUM_ITEMS, VIRTIO_SND_R_CTL_READ, VIRTIO_SND_R_CTL_WRITE, VIRTIO_SND_R_CTL_TLV_READ, VIRTIO_SND_R_CTL_TLV_WRITE, VIRTIO_SND_R_CTL_TLV_COMMAND, ... }; And the device can send the following audio control event notification: enum { ... /* control element event types */ VIRTIO_SND_EVT_CTL_NOTIFY = 0x1200, ... }; See additional details in [1]. [1] https://lists.oasis-open.org/archives/virtio-comment/202104/msg00013.html Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com> Signed-off-by: Aiswarya Cyriac <aiswarya.cyriac@opensynergy.com> Link: https://lore.kernel.org/r/20240115133654.576068-2-aiswarya.cyriac@opensynergy.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
2021-03-07ALSA: virtio: add virtio sound driverAnton Yakovlev
Introduce skeleton of the virtio sound driver. The driver implements the virtio sound device specification, which has become part of the virtio standard. Initial initialization of the device, virtqueues and creation of an empty ALSA sound device. Signed-off-by: Anton Yakovlev <anton.yakovlev@opensynergy.com> Link: https://lore.kernel.org/r/20210302164709.3142702-3-anton.yakovlev@opensynergy.com Signed-off-by: Takashi Iwai <tiwai@suse.de>