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

Signed-off-by: Anton Yakovlev <anton.yakov...@opensynergy.com>
---
 sound/virtio/virtio_card.c    | 57 +++++++++++++++++++++++++++++++++++
 sound/virtio/virtio_pcm.c     |  1 +
 sound/virtio/virtio_pcm_ops.c | 44 ++++++++++++++++++++-------
 3 files changed, 91 insertions(+), 11 deletions(-)

diff --git a/sound/virtio/virtio_card.c b/sound/virtio/virtio_card.c
index 787a4dec1da8..1f0a0fa7bbc0 100644
--- a/sound/virtio/virtio_card.c
+++ b/sound/virtio/virtio_card.c
@@ -373,6 +373,59 @@ static void virtsnd_config_changed(struct virtio_device 
*vdev)
                         "sound device configuration was changed\n");
 }
 
+#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;
+
+       /* Stop all the virtqueues. */
+       vdev->config->reset(vdev);
+       vdev->config->del_vqs(vdev);
+
+       virtsnd_ctl_msg_cancel_all(snd);
+
+       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;
+}
+
+/**
+ * virtsnd_restore() - Resume device.
+ * @vdev: VirtIO parent device.
+ *
+ * Context: Any context.
+ * Return: 0 on success, -errno on failure.
+ */
+static int virtsnd_restore(struct virtio_device *vdev)
+{
+       struct virtio_snd *snd = vdev->priv;
+       int rc;
+
+       rc = virtsnd_find_vqs(snd);
+       if (rc)
+               return rc;
+
+       virtio_device_ready(vdev);
+
+       virtsnd_enable_event_vq(snd);
+
+       return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
 static const struct virtio_device_id id_table[] = {
        { VIRTIO_ID_SOUND, VIRTIO_DEV_ANY_ID },
        { 0 },
@@ -386,6 +439,10 @@ static struct virtio_driver virtsnd_driver = {
        .probe = virtsnd_probe,
        .remove = virtsnd_remove,
        .config_changed = virtsnd_config_changed,
+#ifdef CONFIG_PM_SLEEP
+       .freeze = virtsnd_freeze,
+       .restore = virtsnd_restore,
+#endif
 };
 
 static int __init init(void)
diff --git a/sound/virtio/virtio_pcm.c b/sound/virtio/virtio_pcm.c
index 5f7b4090c6a2..d7471e0a9d04 100644
--- 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;
 
        if (!info->channels_min || info->channels_min > info->channels_max) {
diff --git a/sound/virtio/virtio_pcm_ops.c b/sound/virtio/virtio_pcm_ops.c
index 07510778b555..ccef64502c13 100644
--- a/sound/virtio/virtio_pcm_ops.c
+++ b/sound/virtio/virtio_pcm_ops.c
@@ -218,6 +218,10 @@ static int virtsnd_pcm_hw_params(struct snd_pcm_substream 
*substream,
        if (rc)
                return rc;
 
+       /* If messages have already been allocated before, do nothing. */
+       if (runtime->status->state == SNDRV_PCM_STATE_SUSPENDED)
+               return 0;
+
        return virtsnd_pcm_msg_alloc(vss, periods, period_bytes);
 }
 
@@ -258,19 +262,21 @@ static int virtsnd_pcm_prepare(struct snd_pcm_substream 
*substream)
        }
 
        spin_lock_irqsave(&vss->lock, flags);
-       /*
-        * Since I/O messages are asynchronous, they can be completed
-        * when the runtime structure no longer exists. Since each
-        * completion implies incrementing the hw_ptr, we cache all the
-        * current values needed to compute the new hw_ptr value.
-        */
-       vss->frame_bytes = runtime->frame_bits >> 3;
-       vss->period_size = runtime->period_size;
-       vss->buffer_size = runtime->buffer_size;
+       if (runtime->status->state != SNDRV_PCM_STATE_SUSPENDED) {
+               /*
+                * Since I/O messages are asynchronous, they can be completed
+                * when the runtime structure no longer exists. Since each
+                * completion implies incrementing the hw_ptr, we cache all the
+                * current values needed to compute the new hw_ptr value.
+                */
+               vss->frame_bytes = runtime->frame_bits >> 3;
+               vss->period_size = runtime->period_size;
+               vss->buffer_size = runtime->buffer_size;
 
-       vss->hw_ptr = 0;
+               vss->hw_ptr = 0;
+               vss->msg_last_enqueued = -1;
+       }
        vss->xfer_xrun = false;
-       vss->msg_last_enqueued = -1;
        vss->msg_count = 0;
        spin_unlock_irqrestore(&vss->lock, flags);
 
@@ -300,6 +306,21 @@ 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;
+
+               fallthrough;
+       }
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: {
                struct virtio_snd_queue *queue = virtsnd_pcm_queue(vss);
@@ -326,6 +347,7 @@ static int virtsnd_pcm_trigger(struct snd_pcm_substream 
*substream, int command)
 
                return virtsnd_ctl_msg_send_sync(snd, msg);
        }
+       case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH: {
                spin_lock_irqsave(&vss->lock, flags);
-- 
2.30.0


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