From 323ec0b51bf77249c289df50777843c8f48dc7e7 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Mon, 26 Sep 2022 17:17:05 +0200
Subject: [PATCH] pulse-server: improve maxlength calculations

When no maxlength is given, we use the MAXLENGTH value but we need to
round it DOWN (instead of up) because our buffer is only MAXLENGTH big.
Use CLAMP where we can.
When in capture mode, the maxlength exceeds MAXLENGTH, scale down the
fragsize instead.

Fixes noise in audacious when playing 6 channels sounds. float32 * 6
channels with the maximum buffer size would result in the ringbuffer
being overwritten.
---
 .../module-protocol-pulse/pulse-server.c      | 39 ++++++++++++-------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/modules/module-protocol-pulse/pulse-server.c b/src/modules/module-protocol-pulse/pulse-server.c
index 8fb96cb55..7cbe275bc 100644
--- a/src/modules/module-protocol-pulse/pulse-server.c
+++ b/src/modules/module-protocol-pulse/pulse-server.c
@@ -455,7 +455,7 @@ static void clamp_latency(struct stream *s, struct spa_fraction *lat)
 static uint64_t fix_playback_buffer_attr(struct stream *s, struct buffer_attr *attr,
 		uint32_t rate, struct spa_fraction *lat)
 {
-	uint32_t frame_size, max_prebuf, minreq, latency, max_latency;
+	uint32_t frame_size, max_prebuf, minreq, latency, max_latency, maxlength;
 	struct defs *defs = &s->impl->defs;
 
 	if ((frame_size = s->frame_size) == 0)
@@ -463,24 +463,26 @@ static uint64_t fix_playback_buffer_attr(struct stream *s, struct buffer_attr *a
 	if (frame_size == 0)
 		frame_size = 4;
 
-	pw_log_info("[%s] maxlength:%u tlength:%u minreq:%u prebuf:%u",
+	maxlength = SPA_ROUND_DOWN(MAXLENGTH, frame_size);
+
+	pw_log_info("[%s] maxlength:%u tlength:%u minreq:%u prebuf:%u max:%u",
 			s->client->name, attr->maxlength, attr->tlength,
-			attr->minreq, attr->prebuf);
+			attr->minreq, attr->prebuf, maxlength);
 
 	minreq = frac_to_bytes_round_up(s->min_req, &s->ss);
 	max_latency = defs->quantum_limit * frame_size;
 
-	if (attr->maxlength == (uint32_t) -1 || attr->maxlength > MAXLENGTH)
-		attr->maxlength = MAXLENGTH;
-	attr->maxlength = SPA_ROUND_UP(attr->maxlength, frame_size);
+	if (attr->maxlength == (uint32_t) -1 || attr->maxlength > maxlength)
+		attr->maxlength = maxlength;
+	else
+		attr->maxlength = SPA_ROUND_DOWN(attr->maxlength, frame_size);
 
 	minreq = SPA_MIN(minreq, attr->maxlength);
 
 	if (attr->tlength == (uint32_t) -1)
 		attr->tlength = frac_to_bytes_round_up(s->default_tlength, &s->ss);
-	attr->tlength = SPA_MIN(attr->tlength, attr->maxlength);
+	attr->tlength = SPA_CLAMP(attr->tlength, minreq, attr->maxlength);
 	attr->tlength = SPA_ROUND_UP(attr->tlength, frame_size);
-	attr->tlength = SPA_MAX(attr->tlength, minreq);
 
 	if (attr->minreq == (uint32_t) -1) {
 		uint32_t process = frac_to_bytes_round_up(s->default_req, &s->ss);
@@ -655,35 +657,42 @@ static int reply_create_playback_stream(struct stream *stream, struct pw_manager
 static uint64_t fix_record_buffer_attr(struct stream *s, struct buffer_attr *attr,
 		uint32_t rate, struct spa_fraction *lat)
 {
-	uint32_t frame_size, minfrag, latency;
+	uint32_t frame_size, minfrag, latency, maxlength;
 
 	if ((frame_size = s->frame_size) == 0)
 		frame_size = sample_spec_frame_size(&s->ss);
 	if (frame_size == 0)
 		frame_size = 4;
 
+	maxlength = SPA_ROUND_DOWN(MAXLENGTH, frame_size);
+
 	pw_log_info("[%s] maxlength:%u fragsize:%u framesize:%u",
 			s->client->name, attr->maxlength, attr->fragsize,
 			frame_size);
 
-	if (attr->maxlength == (uint32_t) -1 || attr->maxlength > MAXLENGTH)
-		attr->maxlength = MAXLENGTH;
-	attr->maxlength -= attr->maxlength % frame_size;
+	if (attr->maxlength == (uint32_t) -1 || attr->maxlength > maxlength)
+		attr->maxlength = maxlength;
+	else
+		attr->maxlength = SPA_ROUND_DOWN(attr->maxlength, frame_size);
 	attr->maxlength = SPA_MAX(attr->maxlength, frame_size);
 
 	minfrag = frac_to_bytes_round_up(s->min_frag, &s->ss);
 
 	if (attr->fragsize == (uint32_t) -1 || attr->fragsize == 0)
 		attr->fragsize = frac_to_bytes_round_up(s->default_frag, &s->ss);
-	attr->fragsize = SPA_MIN(attr->fragsize, attr->maxlength);
+	attr->fragsize = SPA_CLAMP(attr->fragsize, minfrag, attr->maxlength);
 	attr->fragsize = SPA_ROUND_UP(attr->fragsize, frame_size);
-	attr->fragsize = SPA_MAX(attr->fragsize, minfrag);
 
 	attr->tlength = attr->minreq = attr->prebuf = 0;
 
 	/* make sure we can queue at least to fragsize without overruns */
-	if (attr->maxlength < attr->fragsize * 4)
+	if (attr->maxlength < attr->fragsize * 4) {
 		attr->maxlength = attr->fragsize * 4;
+		if (attr->maxlength > maxlength) {
+			attr->maxlength = maxlength;
+			attr->fragsize = SPA_ROUND_DOWN(maxlength / 4, frame_size);
+		}
+	}
 
 	latency = attr->fragsize;