[PATCH v8 10/14] ALSA: virtio: prioritize staged capture period work

[Joonho Lee]

Queue staged capture period notifications on system_highpri_wq through
the common scheduling helper. This allows capture notifications to make
progress when ordinary workqueue workers are delayed by CPU contention.
Playback and ordinary capture keep schedule_work().

This preserves the existing priority proposal without mixing RESET or
lifecycle changes into it. It provides no hard real-time deadline and
cannot prevent a userspace reader from overrunning its buffer.

Assisted-by: LLM
Signed-off-by: Joonho Lee <mynameisjune111@xxxxxxxxx>

---
diff --git a/sound/virtio/virtio_pcm.h b/sound/virtio/virtio_pcm.h
--- a/sound/virtio/virtio_pcm.h
+++ b/sound/virtio/virtio_pcm.h
@@ -146,10 +146,14 @@
 	runtime->stop_operating = true;
 }
 
-/* Use one notification helper for all producers. */
+/* Keep non-staged PCM notifications on schedule_work()'s normal queue. */
 static inline bool
 virtsnd_pcm_schedule_period_elapsed(struct virtio_pcm_substream *vss)
 {
+	if (vss->direction == SNDRV_PCM_STREAM_CAPTURE &&
+	    vss->capture_staging)
+		return queue_work(system_highpri_wq, &vss->elapsed_period);
+
 	return schedule_work(&vss->elapsed_period);
 }