[PATCH] pcm_rate: Do not discard slave reported delay in status result.

[Alan Young <Alan.Young@IEE.org>]

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Similar to recent dshare patch.


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>From da687e77261f5cdd3c4b373156fb68ed83d98a26 Mon Sep 17 00:00:00 2001
From: Alan Young <consult.awy@gmail.com>
Date: Tue, 14 Jun 2016 10:15:01 +0100
Subject: [PATCH] pcm_rate: Do not discard slave reported delay in status
 result.

snd_pcm_rate_status() gets the underlying status from the slave PCM.
This may contain a delay value that includes elements such as codec and
other transfer delays. Use this as the base for the returned delay
value, adjusted for any frames buffered locally (within the rate
plugin).

Also update snd_pcm_rate_delay() similarly.
---
 src/pcm/pcm_rate.c | 46 ++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 40 insertions(+), 6 deletions(-)

diff --git a/src/pcm/pcm_rate.c b/src/pcm/pcm_rate.c
index 6184def..15383ae 100644
--- a/src/pcm/pcm_rate.c
+++ b/src/pcm/pcm_rate.c
@@ -559,10 +559,9 @@ snd_pcm_rate_read_areas1(snd_pcm_t *pcm,
 		   pcm->channels, rate);
 }
 
-static inline void snd_pcm_rate_sync_hwptr(snd_pcm_t *pcm)
+static inline void snd_pcm_rate_sync_hwptr0(snd_pcm_t *pcm, snd_pcm_uframes_t slave_hw_ptr)
 {
 	snd_pcm_rate_t *rate = pcm->private_data;
-	snd_pcm_uframes_t slave_hw_ptr = *rate->gen.slave->hw.ptr;
 
 	if (pcm->stream != SND_PCM_STREAM_PLAYBACK)
 		return;
@@ -576,6 +575,12 @@ static inline void snd_pcm_rate_sync_hwptr(snd_pcm_t *pcm)
 	rate->hw_ptr %= pcm->boundary;
 }
 
+static inline void snd_pcm_rate_sync_hwptr(snd_pcm_t *pcm)
+{
+	snd_pcm_rate_t *rate = pcm->private_data;
+	snd_pcm_rate_sync_hwptr0(pcm, *rate->gen.slave->hw.ptr);
+}
+
 static int snd_pcm_rate_hwsync(snd_pcm_t *pcm)
 {
 	snd_pcm_rate_t *rate = pcm->private_data;
@@ -586,10 +591,37 @@ static int snd_pcm_rate_hwsync(snd_pcm_t *pcm)
 	return 0;
 }
 
+static snd_pcm_uframes_t snd_pcm_rate_playback_internal_delay(snd_pcm_t *pcm)
+{
+	snd_pcm_rate_t *rate = pcm->private_data;
+
+	if (rate->appl_ptr < rate->last_commit_ptr) {
+		return rate->appl_ptr - rate->last_commit_ptr + pcm->boundary;
+	} else {
+		return rate->appl_ptr - rate->last_commit_ptr;
+	}
+}
+
 static int snd_pcm_rate_delay(snd_pcm_t *pcm, snd_pcm_sframes_t *delayp)
 {
+	snd_pcm_rate_t *rate = pcm->private_data;
+	snd_pcm_sframes_t slave_delay;
+	int err;
+
 	snd_pcm_rate_hwsync(pcm);
-	*delayp = snd_pcm_mmap_hw_avail(pcm);
+
+	err = snd_pcm_delay(rate->gen.slave, &slave_delay);
+	if (err < 0) {
+		return err;
+	}
+
+	if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
+		*delayp = rate->ops.input_frames(rate->obj, slave_delay)
+				+ snd_pcm_rate_playback_internal_delay(pcm);
+	} else {
+		*delayp = rate->ops.output_frames(rate->obj, slave_delay)
+				+ snd_pcm_mmap_capture_hw_avail(pcm);
+	}
 	return 0;
 }
 
@@ -1083,15 +1115,17 @@ static int snd_pcm_rate_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
 			status->state = SND_PCM_STATE_RUNNING;
 		status->trigger_tstamp = rate->trigger_tstamp;
 	}
-	snd_pcm_rate_sync_hwptr(pcm);
+	snd_pcm_rate_sync_hwptr0(rate, status->hw_ptr);
 	status->appl_ptr = *pcm->appl.ptr;
 	status->hw_ptr = *pcm->hw.ptr;
 	if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
-		status->delay = snd_pcm_mmap_playback_hw_avail(pcm);
+		status->delay = rate->ops.input_frames(rate->obj, status->delay)
+					+ snd_pcm_rate_playback_internal_delay(pcm);
 		status->avail = snd_pcm_mmap_playback_avail(pcm);
 		status->avail_max = rate->ops.input_frames(rate->obj, status->avail_max);
 	} else {
-		status->delay = snd_pcm_mmap_capture_hw_avail(pcm);
+		status->delay = rate->ops.output_frames(rate->obj, status->delay)
+					+ snd_pcm_mmap_capture_hw_avail(pcm);
 		status->avail = snd_pcm_mmap_capture_avail(pcm);
 		status->avail_max = rate->ops.output_frames(rate->obj, status->avail_max);
 	}
-- 
2.5.5


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