On Sat, 27 Feb 2021 09:59:56 +0100,
Anton Yakovlev wrote:
>
> All running PCM substreams are stopped on device suspend and restarted
> on device resume.
>
> Signed-off-by: Anton Yakovlev <anton.yakovlev@xxxxxxxxxxxxxxx>
> ---
> sound/virtio/virtio_card.c | 56 +++++++++++++++++++++++++++++++++++
> sound/virtio/virtio_pcm.c | 1 +
> sound/virtio/virtio_pcm_ops.c | 41 ++++++++++++++++++++-----
> 3 files changed, 90 insertions(+), 8 deletions(-)
>
> diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
> index 59455a562018..c7ae8801991d 100644
> --- a/sound/virtio/virtio_card.c
> +++ b/sound/virtio/virtio_card.c
> @@ -323,6 +323,58 @@ static void virtsnd_remove(struct virtio_device *vdev)
> kfree(snd->event_msgs);
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +/**
> + * virtsnd_freeze() - Suspend device.
> + * @vdev: VirtIO parent device.
> + *
> + * Context: Any context.
> + * Return: 0 on success, -errno on failure.
> + */
> +static int virtsnd_freeze(struct virtio_device *vdev)
> +{
> + struct virtio_snd *snd = vdev->priv;
> +
> + virtsnd_ctl_msg_cancel_all(snd);
> +
> + vdev->config->del_vqs(vdev);
> + vdev->config->reset(vdev);
> +
> + kfree(snd->event_msgs);
> +
> + /*
> + * If the virtsnd_restore() fails before re-allocating events, then we
> + * get a dangling pointer here.
> + */
> + snd->event_msgs = NULL;
> +
> + return 0;
I suppose some cancel of inflight works is needed?
Ditto for the device removal, too.
> --- a/sound/virtio/virtio_pcm.c
> +++ b/sound/virtio/virtio_pcm.c
> @@ -109,6 +109,7 @@ static int virtsnd_pcm_build_hw(struct virtio_pcm_substream *vss,
> SNDRV_PCM_INFO_BATCH |
> SNDRV_PCM_INFO_BLOCK_TRANSFER |
> SNDRV_PCM_INFO_INTERLEAVED |
> + SNDRV_PCM_INFO_RESUME |
> SNDRV_PCM_INFO_PAUSE;
Actually you don't need to set SNDRV_PCM_INFO_RESUME.
This flag means that the driver supports the full resume procedure,
which isn't often the case; with this, the driver is supposed to
resume the stream exactly from the suspended position.
Most drivers don't set this but implement only the suspend-stop
action. Then the application (or the sound backend) will re-setup the
stream and restart accordingly.
> @@ -309,6 +318,21 @@ static int virtsnd_pcm_trigger(struct snd_pcm_substream *substream, int command)
> int rc;
>
> switch (command) {
> + case SNDRV_PCM_TRIGGER_RESUME: {
> + /*
> + * We restart the substream by executing the standard command
> + * sequence.
> + */
> + rc = virtsnd_pcm_hw_params(substream, NULL);
> + if (rc)
> + return rc;
> +
> + rc = virtsnd_pcm_prepare(substream);
> + if (rc)
> + return rc;
And this won't work at all unless nonatomic PCM ops.
thanks,
Takashi
