[RFC PATCH v3 1/2] ALSA: pcm: allow capture reads while draining
flat view
COOLING7d
SUPERSEDED
From: Joonho Lee <hidden>
Date: 2026-10-14 15:24:39
Also in:
linux-sound, lkml
Subsystem:
sound, the rest · Maintainers:
Jaroslav Kysela, Takashi Iwai, Linus Torvalds
Revision v3 of 5 in this series.
Revisions (5)
Allow capture transfer calls in DRAINING so already captured tail frames remain readable until drain completes. Assisted-by: LLM Signed-off-by: Joonho Lee <redacted> --- sound/core/pcm_lib.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 4d665b4148d7..de952f639d3b 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c@@ -2208,13 +2208,17 @@ static int pcm_sanity_check(struct snd_pcm_substream *substream) return 0; } -static int pcm_accessible_state(struct snd_pcm_runtime *runtime) +static int pcm_accessible_state(struct snd_pcm_substream *substream) { + struct snd_pcm_runtime *runtime = substream->runtime; + switch (runtime->state) { case SNDRV_PCM_STATE_PREPARED: case SNDRV_PCM_STATE_RUNNING: case SNDRV_PCM_STATE_PAUSED: return 0; + case SNDRV_PCM_STATE_DRAINING: + return substream->stream == SNDRV_PCM_STREAM_CAPTURE ? 0 : -EBADFD; case SNDRV_PCM_STATE_XRUN: return -EPIPE; case SNDRV_PCM_STATE_SUSPENDED:
@@ -2320,7 +2324,7 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream, nonblock = !!(substream->f_flags & O_NONBLOCK); snd_pcm_stream_lock_irq(substream); - err = pcm_accessible_state(runtime); + err = pcm_accessible_state(substream); if (err < 0) goto _end_unlock;
@@ -2388,7 +2392,7 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream, atomic_dec(&runtime->buffer_accessing); if (err < 0) goto _end_unlock; - err = pcm_accessible_state(runtime); + err = pcm_accessible_state(substream); if (err < 0) goto _end_unlock; appl_ptr += frames;