[PATCH - JACK IO plug 0/3] snd_pcm_drain support

[PATCH - JACK IO plug 0/3] snd_pcm_drain support

[twischer]

The following patches are required to support draining with the JACK IO plugin.
Without these patches
$ speaker-test -D jack -c2
will freeze.

It is required to support the draining feature implemented in 
commit ce2095c41f2 (pcm: ioplug: Implement proper drain behavior)

[PATCH - JACK IO plug 1/1] pcm: ioplug: Provide avail helper function for plugins

[twischer]

From: Timo Wischer <twischer@de.adit-jv.com>

This function can be called without calling snd_pcm_avail_update().

The call to snd_pcm_avail_update() can take some time.
Therefore some developers would not like to call it from a real-time
context (e.g. from JACK client context).

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

diff --git a/include/pcm_ioplug.h b/include/pcm_ioplug.h
index c1310e3..b16fc8b 100644
--- a/include/pcm_ioplug.h
+++ b/include/pcm_ioplug.h
@@ -235,6 +235,9 @@ int snd_pcm_ioplug_set_param_list(snd_pcm_ioplug_t *io, int type, unsigned int n
 int snd_pcm_ioplug_set_state(snd_pcm_ioplug_t *ioplug, snd_pcm_state_t state);
 
 /* calucalte the available frames */
+snd_pcm_uframes_t snd_pcm_ioplug_avail(const snd_pcm_ioplug_t * const ioplug,
+				       const snd_pcm_uframes_t hw_ptr,
+				       const snd_pcm_uframes_t appl_ptr);
 snd_pcm_uframes_t snd_pcm_ioplug_hw_avail(const snd_pcm_ioplug_t * const ioplug,
 					  const snd_pcm_uframes_t hw_ptr,
 					  const snd_pcm_uframes_t appl_ptr);
diff --git a/src/pcm/pcm_ioplug.c b/src/pcm/pcm_ioplug.c
index 4d44ae2..6d52c27 100644
--- a/src/pcm/pcm_ioplug.c
+++ b/src/pcm/pcm_ioplug.c
@@ -1221,6 +1221,21 @@ int snd_pcm_ioplug_set_state(snd_pcm_ioplug_t *ioplug, snd_pcm_state_t state)
  * \param ioplug the ioplug handle
  * \param hw_ptr hardware pointer in frames
  * \param appl_ptr application pointer in frames
+ * \return available frames for the application
+ */
+snd_pcm_uframes_t snd_pcm_ioplug_avail(const snd_pcm_ioplug_t * const ioplug,
+				       const snd_pcm_uframes_t hw_ptr,
+				       const snd_pcm_uframes_t appl_ptr)
+{
+	return __snd_pcm_avail(ioplug->pcm, hw_ptr, appl_ptr);
+}
+
+/**
+ * \brief Get the available frames. This function can be used to calculate the
+ * the available frames before calling #snd_pcm_avail_update()
+ * \param ioplug the ioplug handle
+ * \param hw_ptr hardware pointer in frames
+ * \param appl_ptr application pointer in frames
  * \return available frames for the hardware
  */
 snd_pcm_uframes_t snd_pcm_ioplug_hw_avail(const snd_pcm_ioplug_t * const ioplug,
@@ -1230,8 +1245,9 @@ snd_pcm_uframes_t snd_pcm_ioplug_hw_avail(const snd_pcm_ioplug_t * const ioplug,
 	/* available data/space which can be transferred by the user
 	 * application
 	 */
-	const snd_pcm_uframes_t user_avail = __snd_pcm_avail(ioplug->pcm,
-							     hw_ptr, appl_ptr);
+	const snd_pcm_uframes_t user_avail = snd_pcm_ioplug_avail(ioplug,
+								  hw_ptr,
+								  appl_ptr);
 
 	if (user_avail > ioplug->pcm->buffer_size) {
 		/* there was an Xrun */
-- 
2.7.4

[PATCH - JACK IO plug 1/2] jack: Avoid call to snd_pcm_avail_update() from JACK thread

[twischer]

From: Timo Wischer <twischer@de.adit-jv.com>

snd_pcm_avail_update() can call snd_pcm_jack_stop() but
snd_pcm_jack_stop() should not be called by the JACK thread.
It should only be called by the thread how has called
snd_pcm_jack_start().

In addition the execution of snd_pcm_avail_update() can take a while.
Therefore it should not be called by the JACK thread to not block this
thread.

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
index e3df4d2..b643d93 100644
--- a/jack/pcm_jack.c
+++ b/jack/pcm_jack.c
@@ -67,7 +67,7 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
 
 	if (io->state == SND_PCM_STATE_RUNNING ||
 	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
-		avail = snd_pcm_avail_update(io->pcm);
+		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
 		if (avail >= 0 && avail < jack->min_avail) {
 			while (read(io->poll_fd, &buf, sizeof(buf)) == sizeof(buf))
 				;
@@ -84,7 +84,7 @@ static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
 	snd_pcm_sframes_t avail;
 	snd_pcm_jack_t *jack = io->private_data;
 
-	avail = snd_pcm_avail_update(io->pcm);
+	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
 	if (avail < 0 || avail >= jack->min_avail) {
 		write(jack->fd, &buf, 1);
 		return 1;
-- 
2.7.4

Re: [PATCH - JACK IO plug 1/2] jack: Avoid call to snd_pcm_avail_update() from JACK thread

[Takashi Iwai]

On Tue, 03 Jul 2018 13:58:06 +0200,
<twischer@de.adit-jv.com> wrote:
> 
> From: Timo Wischer <twischer@de.adit-jv.com>
> 
> snd_pcm_avail_update() can call snd_pcm_jack_stop() but
> snd_pcm_jack_stop() should not be called by the JACK thread.
> It should only be called by the thread how has called
> snd_pcm_jack_start().
> 
> In addition the execution of snd_pcm_avail_update() can take a while.
> Therefore it should not be called by the JACK thread to not block this
> thread.
> 
> Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

With that change, avail cannot be a negative, as
snd_pcm_ioplug_avail() returns snd_pcm_uframes_t.
A couple of checks are redundant and confuse readers as if it's still
a signed value.


Takashi


> 
> diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
> index e3df4d2..b643d93 100644
> --- a/jack/pcm_jack.c
> +++ b/jack/pcm_jack.c
> @@ -67,7 +67,7 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
>  
>  	if (io->state == SND_PCM_STATE_RUNNING ||
>  	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
> -		avail = snd_pcm_avail_update(io->pcm);
> +		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
>  		if (avail >= 0 && avail < jack->min_avail) {
>  			while (read(io->poll_fd, &buf, sizeof(buf)) == sizeof(buf))
>  				;
> @@ -84,7 +84,7 @@ static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
>  	snd_pcm_sframes_t avail;
>  	snd_pcm_jack_t *jack = io->private_data;
>  
> -	avail = snd_pcm_avail_update(io->pcm);
> +	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
>  	if (avail < 0 || avail >= jack->min_avail) {
>  		write(jack->fd, &buf, 1);
>  		return 1;
> -- 
> 2.7.4
> 

[PATCH - JACK IO plug 1/2] jack: Avoid call to snd_pcm_avail_update() from JACK thread

[twischer]

From: Timo Wischer <twischer@de.adit-jv.com>

snd_pcm_avail_update() can call snd_pcm_jack_stop() but
snd_pcm_jack_stop() should not be called by the JACK thread.
It should only be called by the thread how has called
snd_pcm_jack_start().

In addition the execution of snd_pcm_avail_update() can take a while.
Therefore it should not be called by the JACK thread to not block this
thread.

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
index e3df4d2..5a57e13 100644
--- a/jack/pcm_jack.c
+++ b/jack/pcm_jack.c
@@ -62,13 +62,13 @@ static int snd_pcm_jack_stop(snd_pcm_ioplug_t *io);
 static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
 {
 	static char buf[32];
-	snd_pcm_sframes_t avail;
+	snd_pcm_uframes_t avail;
 	snd_pcm_jack_t *jack = io->private_data;
 
 	if (io->state == SND_PCM_STATE_RUNNING ||
 	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
-		avail = snd_pcm_avail_update(io->pcm);
-		if (avail >= 0 && avail < jack->min_avail) {
+		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
+		if (avail < jack->min_avail) {
 			while (read(io->poll_fd, &buf, sizeof(buf)) == sizeof(buf))
 				;
 			return 1;
@@ -81,11 +81,11 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
 static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
 {
 	static char buf[1];
-	snd_pcm_sframes_t avail;
+	snd_pcm_uframes_t avail;
 	snd_pcm_jack_t *jack = io->private_data;
 
-	avail = snd_pcm_avail_update(io->pcm);
-	if (avail < 0 || avail >= jack->min_avail) {
+	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
+	if (avail >= jack->min_avail) {
 		write(jack->fd, &buf, 1);
 		return 1;
 	}
-- 
2.7.4

Re: [PATCH - JACK IO plug 1/2] jack: Avoid call to snd_pcm_avail_update() from JACK thread

[Takashi Iwai]

On Tue, 03 Jul 2018 14:23:59 +0200,
<twischer@de.adit-jv.com> wrote:
> 
> From: Timo Wischer <twischer@de.adit-jv.com>
> 
> snd_pcm_avail_update() can call snd_pcm_jack_stop() but
> snd_pcm_jack_stop() should not be called by the JACK thread.
> It should only be called by the thread how has called
> snd_pcm_jack_start().
> 
> In addition the execution of snd_pcm_avail_update() can take a while.
> Therefore it should not be called by the JACK thread to not block this
> thread.
> 
> Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

Please put "v2" into the subject prefix, and give a brief information
what changed from v1 to v2.  And, don't attach to the old mail
thread.  As of this post, it's utterly confusing which patch is which
version!


thanks,

Takashi

> 
> diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
> index e3df4d2..5a57e13 100644
> --- a/jack/pcm_jack.c
> +++ b/jack/pcm_jack.c
> @@ -62,13 +62,13 @@ static int snd_pcm_jack_stop(snd_pcm_ioplug_t *io);
>  static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
>  {
>  	static char buf[32];
> -	snd_pcm_sframes_t avail;
> +	snd_pcm_uframes_t avail;
>  	snd_pcm_jack_t *jack = io->private_data;
>  
>  	if (io->state == SND_PCM_STATE_RUNNING ||
>  	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
> -		avail = snd_pcm_avail_update(io->pcm);
> -		if (avail >= 0 && avail < jack->min_avail) {
> +		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
> +		if (avail < jack->min_avail) {
>  			while (read(io->poll_fd, &buf, sizeof(buf)) == sizeof(buf))
>  				;
>  			return 1;
> @@ -81,11 +81,11 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
>  static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
>  {
>  	static char buf[1];
> -	snd_pcm_sframes_t avail;
> +	snd_pcm_uframes_t avail;
>  	snd_pcm_jack_t *jack = io->private_data;
>  
> -	avail = snd_pcm_avail_update(io->pcm);
> -	if (avail < 0 || avail >= jack->min_avail) {
> +	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
> +	if (avail >= jack->min_avail) {
>  		write(jack->fd, &buf, 1);
>  		return 1;
>  	}
> -- 
> 2.7.4
> 
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
> 

[PATCH - JACK IO plug 2/2] jack: Update poll_fd also in draining state to support snd_pcm_drain

[twischer]

From: Timo Wischer <twischer@de.adit-jv.com>

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
index b643d93..0d1ccb9 100644
--- a/jack/pcm_jack.c
+++ b/jack/pcm_jack.c
@@ -66,6 +66,7 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
 	snd_pcm_jack_t *jack = io->private_data;
 
 	if (io->state == SND_PCM_STATE_RUNNING ||
+	    io->state == SND_PCM_STATE_DRAINING ||
 	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
 		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
 		if (avail >= 0 && avail < jack->min_avail) {
@@ -85,7 +86,13 @@ static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
 	snd_pcm_jack_t *jack = io->private_data;
 
 	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
-	if (avail < 0 || avail >= jack->min_avail) {
+	/* In draining state poll_fd is used to wait
+	 * till all pending frames are played.
+	 * Therefore it has to be guarantee that a poll event is also generated
+	 * if the buffer contains less than min_avail frames
+	 */
+	if (avail < 0 || avail >= jack->min_avail ||
+	    io->state == SND_PCM_STATE_DRAINING) {
 		write(jack->fd, &buf, 1);
 		return 1;
 	}
@@ -161,7 +168,8 @@ snd_pcm_jack_process_cb(jack_nframes_t nframes, snd_pcm_ioplug_t *io)
 		jack->areas[channel].step = jack->sample_bits;
 	}
 
-	if (io->state == SND_PCM_STATE_RUNNING) {
+	if (io->state == SND_PCM_STATE_RUNNING ||
+	    io->state == SND_PCM_STATE_DRAINING) {
 		snd_pcm_uframes_t hw_ptr = jack->hw_ptr;
 		const snd_pcm_uframes_t hw_avail = snd_pcm_ioplug_hw_avail(io, hw_ptr,
 									   io->appl_ptr);
-- 
2.7.4

[PATCH - JACK IO plug 2/2] jack: Update poll_fd also in draining state to support snd_pcm_drain

[twischer]

From: Timo Wischer <twischer@de.adit-jv.com>

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
index 5a57e13..98a6f7e 100644
--- a/jack/pcm_jack.c
+++ b/jack/pcm_jack.c
@@ -66,6 +66,7 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
 	snd_pcm_jack_t *jack = io->private_data;
 
 	if (io->state == SND_PCM_STATE_RUNNING ||
+	    io->state == SND_PCM_STATE_DRAINING ||
 	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
 		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
 		if (avail < jack->min_avail) {
@@ -85,7 +86,12 @@ static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
 	snd_pcm_jack_t *jack = io->private_data;
 
 	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
-	if (avail >= jack->min_avail) {
+	/* In draining state poll_fd is used to wait
+	 * till all pending frames are played.
+	 * Therefore it has to be guarantee that a poll event is also generated
+	 * if the buffer contains less than min_avail frames
+	 */
+	if (avail >= jack->min_avail || io->state == SND_PCM_STATE_DRAINING) {
 		write(jack->fd, &buf, 1);
 		return 1;
 	}
@@ -161,7 +167,8 @@ snd_pcm_jack_process_cb(jack_nframes_t nframes, snd_pcm_ioplug_t *io)
 		jack->areas[channel].step = jack->sample_bits;
 	}
 
-	if (io->state == SND_PCM_STATE_RUNNING) {
+	if (io->state == SND_PCM_STATE_RUNNING ||
+	    io->state == SND_PCM_STATE_DRAINING) {
 		snd_pcm_uframes_t hw_ptr = jack->hw_ptr;
 		const snd_pcm_uframes_t hw_avail = snd_pcm_ioplug_hw_avail(io, hw_ptr,
 									   io->appl_ptr);
-- 
2.7.4

Re: [PATCH - JACK IO plug 2/2] jack: Update poll_fd also in draining state to support snd_pcm_drain

[Takashi Iwai]

On Tue, 03 Jul 2018 14:26:54 +0200,
<twischer@de.adit-jv.com> wrote:
> 
> From: Timo Wischer <twischer@de.adit-jv.com>
> 
> Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>

Please give some change log text to explain why the patch is needed
and what it does.  The empty change log indicates already something
wrong unless it's a really trivial change.


thanks,

Takashi

> 
> diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
> index 5a57e13..98a6f7e 100644
> --- a/jack/pcm_jack.c
> +++ b/jack/pcm_jack.c
> @@ -66,6 +66,7 @@ static int pcm_poll_block_check(snd_pcm_ioplug_t *io)
>  	snd_pcm_jack_t *jack = io->private_data;
>  
>  	if (io->state == SND_PCM_STATE_RUNNING ||
> +	    io->state == SND_PCM_STATE_DRAINING ||
>  	    (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) {
>  		avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
>  		if (avail < jack->min_avail) {
> @@ -85,7 +86,12 @@ static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io)
>  	snd_pcm_jack_t *jack = io->private_data;
>  
>  	avail = snd_pcm_ioplug_avail(io, jack->hw_ptr, io->appl_ptr);
> -	if (avail >= jack->min_avail) {
> +	/* In draining state poll_fd is used to wait
> +	 * till all pending frames are played.
> +	 * Therefore it has to be guarantee that a poll event is also generated
> +	 * if the buffer contains less than min_avail frames
> +	 */
> +	if (avail >= jack->min_avail || io->state == SND_PCM_STATE_DRAINING) {
>  		write(jack->fd, &buf, 1);
>  		return 1;
>  	}
> @@ -161,7 +167,8 @@ snd_pcm_jack_process_cb(jack_nframes_t nframes, snd_pcm_ioplug_t *io)
>  		jack->areas[channel].step = jack->sample_bits;
>  	}
>  
> -	if (io->state == SND_PCM_STATE_RUNNING) {
> +	if (io->state == SND_PCM_STATE_RUNNING ||
> +	    io->state == SND_PCM_STATE_DRAINING) {
>  		snd_pcm_uframes_t hw_ptr = jack->hw_ptr;
>  		const snd_pcm_uframes_t hw_avail = snd_pcm_ioplug_hw_avail(io, hw_ptr,
>  									   io->appl_ptr);
> -- 
> 2.7.4
> 
> _______________________________________________
> Alsa-devel mailing list
> Alsa-devel@alsa-project.org
> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>