linux.git/sound/virtio, branch v6.7

ALSA: virtio: use ack callback

2023-10-27T09:25:07+00:00

This commit uses the ack() callback to determine when a buffer has been
updated, then exposes it to guest.

The current mechanism splits a dma buffer into descriptors that are
exposed to the device. This dma buffer is shared with the user
application. When the device consumes a buffer, the driver moves the
request from the used ring to available ring.

The driver exposes the buffer to the device without knowing if the
content has been updated from the user. The section 2.8.21.1 of the
virtio spec states that: "The device MAY access the descriptor chains
the driver created and the memory they refer to immediately". If the
device picks up buffers from the available ring just after it is
notified, it happens that the content may be old.

When the ack() callback is invoked, the driver exposes only the buffers
that have already been updated, i.e., enqueued in the available ring.
Thus, the device always picks up a buffer that is updated.

For capturing, the driver starts by exposing all the available buffers
to device. After device updates the content of a buffer, it enqueues it
in the used ring. It is only after the ack() for capturing is issued
that the driver re-enqueues the buffer in the available ring.

Co-developed-by: Anton Yakovlev 
Signed-off-by: Anton Yakovlev 
Signed-off-by: Matias Ezequiel Vara Larsen 
Link: https://lore.kernel.org/r/ZTjkn1YAFz67yfqx@fedora
Signed-off-by: Takashi Iwai

virtio: wrap config->reset calls

2022-01-14T23:50:52+00:00

This will enable cleanups down the road.
The idea is to disable cbs, then add "flush_queued_cbs" callback
as a parameter, this way drivers can flush any work
queued after callbacks have been disabled.

Signed-off-by: Michael S. Tsirkin 
Link: https://lore.kernel.org/r/20211013105226.20225-1-mst@redhat.com
Signed-off-by: Michael S. Tsirkin

ALSA: virtio: Replace zero-length array with flexible-array member

2021-09-30T11:47:57+00:00

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

Also, make use of the struct_size() helper in kzalloc().

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Signed-off-by: Gustavo A. R. Silva 
Link: https://lore.kernel.org/r/20210929191504.GA337268@embeddedor
Signed-off-by: Takashi Iwai

ALSA: virtio: fix kernel-doc

2021-04-27T06:39:39+00:00

make W=1 warning:

sound/virtio/virtio_ctl_msg.c:70: warning: expecting prototype for
virtsnd_ctl_msg_request(). Prototype was for
virtsnd_ctl_msg_response() instead

Signed-off-by: Pierre-Louis Bossart 
Link: https://lore.kernel.org/r/20210426213902.234711-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai

ALSA: virtio: use module_virtio_driver() to simplify the code

2021-04-12T10:15:34+00:00

module_virtio_driver() makes the code simpler by eliminating
boilerplate code.

Signed-off-by: Chen Huang 
Reviewed-by: Anton Yakovlev 
Link: https://lore.kernel.org/r/20210408125429.1158703-1-chenhuang5@huawei.com
Signed-off-by: Takashi Iwai

ALSA: virtio: introduce device suspend/resume support

2021-03-07T08:08:39+00:00

All running PCM substreams are stopped on device suspend and restarted
on device resume.

Signed-off-by: Anton Yakovlev 
Link: https://lore.kernel.org/r/20210302164709.3142702-10-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai

ALSA: virtio: introduce PCM channel map support

2021-03-07T08:08:20+00:00

Enumerate all available PCM channel maps and create ALSA controls.

Signed-off-by: Anton Yakovlev 
Link: https://lore.kernel.org/r/20210302164709.3142702-9-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai

ALSA: virtio: introduce jack support

2021-03-07T08:08:11+00:00

Enumerate all available jacks and create ALSA controls.

At the moment jacks have a simple implementation and can only be used
to receive notifications about a plugged in/out device.

Signed-off-by: Anton Yakovlev 
Link: https://lore.kernel.org/r/20210302164709.3142702-8-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai

ALSA: virtio: PCM substream operators

2021-03-07T08:08:03+00:00

Introduce the operators required for the operation of substreams.

Signed-off-by: Anton Yakovlev 
Link: https://lore.kernel.org/r/20210302164709.3142702-7-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai

ALSA: virtio: handling control and I/O messages for the PCM device

2021-03-07T08:07:44+00:00

The driver implements a message-based transport for I/O substream
operations. Before the start of the substream, the hardware buffer is
sliced into I/O messages, the number of which is equal to the current
number of periods. The size of each message is equal to the current
size of one period.

I/O messages are organized in an ordered queue. The completion of the
I/O message indicates an elapsed period (the only exception is the end
of the stream for the capture substream). Upon completion, the message
is automatically re-added to the end of the queue.

Signed-off-by: Anton Yakovlev 
Link: https://lore.kernel.org/r/20210302164709.3142702-6-anton.yakovlev@opensynergy.com
Signed-off-by: Takashi Iwai