From: Andreas Pape <apape@de.adit-jv.com>
Date: Tue, 24 Nov 2020 15:48:03 +0000 (+0100)
Subject: jack: add option to allow non-jack-aligned period size
X-Git-Tag: v1.2.5~6
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=3b6d4fad8ac8361262a6e5efb4b614b1b3dfe764;p=alsa-plugins.git

jack: add option to allow non-jack-aligned period size

Commit 72337f1dcb2df6a2b7fdae93e88d7dd3a7e97ab4 forces ALSA period size
to be exact multiple of the JACK daemon period size.
There are good reasons to align the period size, but completely disallowing non aligned periods is too restrictive.
This patch adds an option "align_psize" which allows to optionally revert to original behavior.

Signed-off-by: Andreas Pape <apape@de.adit-jv.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---

diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c
index 5dc78fb..26674fa 100644
--- a/jack/pcm_jack.c
+++ b/jack/pcm_jack.c
@@ -51,6 +51,7 @@ typedef struct {
 	snd_pcm_uframes_t hw_ptr;
 	unsigned int sample_bits;
 	snd_pcm_uframes_t min_avail;
+	int use_period_alignment;
 
 	snd_pcm_channel_area_t *areas;
 
@@ -450,8 +451,9 @@ static int jack_set_hw_constraint(snd_pcm_jack_t *jack)
 						   jack->num_ports, jack->num_ports)) < 0 ||
 	    (err = snd_pcm_ioplug_set_param_minmax(&jack->io, SND_PCM_IOPLUG_HW_RATE,
 						   rate, rate)) < 0 ||
-	    (err = snd_pcm_ioplug_set_param_list(&jack->io, SND_PCM_IOPLUG_HW_PERIOD_BYTES,
-						 ARRAY_SIZE(psize_list), psize_list)) < 0 ||
+	    (err = jack->use_period_alignment ?
+				snd_pcm_ioplug_set_param_list(&jack->io, SND_PCM_IOPLUG_HW_PERIOD_BYTES, ARRAY_SIZE(psize_list), psize_list) :
+				snd_pcm_ioplug_set_param_minmax(&jack->io, SND_PCM_IOPLUG_HW_PERIOD_BYTES, 128, 64*1024) ) < 0 ||
 	    (err = snd_pcm_ioplug_set_param_minmax(&jack->io, SND_PCM_IOPLUG_HW_PERIODS,
 						   2, 64)) < 0)
 		return err;
@@ -532,6 +534,7 @@ static int snd_pcm_jack_open(snd_pcm_t **pcmp, const char *name,
 			     const char *client_name,
 			     snd_config_t *playback_conf,
 			     snd_config_t *capture_conf,
+			     int use_period_alignment,
 			     snd_pcm_stream_t stream, int mode)
 {
 	snd_pcm_jack_t *jack;
@@ -547,6 +550,7 @@ static int snd_pcm_jack_open(snd_pcm_t **pcmp, const char *name,
 
 	jack->fd = -1;
 	jack->io.poll_fd = -1;
+	jack->use_period_alignment = use_period_alignment;
 
 	err = parse_ports(jack, stream == SND_PCM_STREAM_PLAYBACK ?
 			  playback_conf : capture_conf);
@@ -635,6 +639,7 @@ SND_PCM_PLUGIN_DEFINE_FUNC(jack)
 	snd_config_t *capture_conf = NULL;
 	const char *client_name = NULL;
 	int err;
+	int align_jack_period = 1; /*by default we allow only JACK aligned period size*/
 	
 	snd_config_for_each(i, next, conf) {
 		snd_config_t *n = snd_config_iterator_entry(i);
@@ -663,11 +668,18 @@ SND_PCM_PLUGIN_DEFINE_FUNC(jack)
 			capture_conf = n;
 			continue;
 		}
+		if (strcmp(id, "align_psize") == 0) {
+			err = snd_config_get_bool(n);
+			if (err < 0)
+				return err;
+			align_jack_period = err ? 1 : 0;
+			continue;
+		}
 		SNDERR("Unknown field %s", id);
 		return -EINVAL;
 	}
 
-	err = snd_pcm_jack_open(pcmp, name, client_name, playback_conf, capture_conf, stream, mode);
+	err = snd_pcm_jack_open(pcmp, name, client_name, playback_conf, capture_conf, align_jack_period, stream, mode);
 
 	return err;
 }