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Wed, 14 Oct 2026 01:15:47 -0700 (PDT) From: Joonho Lee To: Takashi Iwai , Jaroslav Kysela Cc: linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: [RFC PATCH v2 1/2] ALSA: pcm: allow capture reads while draining Date: Wed, 14 Oct 2026 17:15:43 +0900 Message-ID: In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Allow capture transfer calls in DRAINING so already captured tail frames remain readable until drain completes. Assisted-by: LLM Signed-off-by: Joonho Lee --- 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;