settings: remove link.min-buffers option again

The min should always be 1. We have other ways of bumping the number of
buffers to 2, like the ASYNC allocation flag which we can set if we are
also doing some async scheduling. We could make this an option later.

Otherwise, we would also allocate 2 buffers by default between the mixer
and the node, which is unnecessary.

doc/dox/config/pipewire.conf.5.md

@@ -217,10 +217,6 @@ Default video rate denominator
 @PAR@ pipewire.conf  library.name.system = support/libspa-support
 The name of the shared library to use for the system functions for the main thread.
 
-@PAR@ pipewire.conf  link.min-buffers = 2
-The minimum number of buffers to negotiate between nodes. Using 1 buffer will consume
-less memory but might cause glitches when using async nodes.
-
 @PAR@ pipewire.conf  link.max-buffers = 64
 The maximum number of buffers to negotiate between nodes. Note that version < 3 clients
 can only support 16 buffers. More buffers is almost always worse than less, latency

src/daemon/minimal.conf.in

@@ -13,7 +13,6 @@ context.properties = {
     #library.name.system                   = support/libspa-support
     #context.data-loop.library.name.system = support/libspa-support
     #support.dbus                          = true
-    #link.min-buffers                      = 2
     #link.max-buffers                      = 64
     link.max-buffers                       = 16                       # version < 3 clients can't handle more
     #mem.warn-mlock                        = false

src/daemon/pipewire.conf.in

@@ -13,7 +13,6 @@ context.properties = {
     #library.name.system                   = support/libspa-support
     #context.data-loop.library.name.system = support/libspa-support
     #support.dbus                          = true
-    #link.min-buffers                      = 2
     #link.max-buffers                      = 64
     link.max-buffers                       = 16                       # version < 3 clients can't handle more
     #mem.warn-mlock                        = false

src/pipewire/buffers.c

@@ -308,7 +308,6 @@ int pw_buffers_negotiate(struct pw_context *context, uint32_t flags,
 
 	if (SPA_FLAG_IS_SET(flags, PW_BUFFERS_FLAG_ASYNC))
 		max_buffers = SPA_MAX(2u, max_buffers);
-	max_buffers = SPA_MAX(context->settings.link_min_buffers, max_buffers);
 
 	if (SPA_FLAG_IS_SET(flags, PW_BUFFERS_FLAG_SHARED_MEM)) {
 		if (types != SPA_ID_INVALID)

src/pipewire/impl-link.c

@@ -588,6 +588,9 @@ static int do_allocation(struct pw_impl_link *this)
 		flags = 0;
 		/* always shared buffers for the link */
 		alloc_flags = PW_BUFFERS_FLAG_SHARED;
+		/* always enable async mode */
+		alloc_flags |= PW_BUFFERS_FLAG_ASYNC;
+
 		if (output->node->remote || input->node->remote)
 			alloc_flags |= PW_BUFFERS_FLAG_SHARED_MEM;
 

src/pipewire/private.h

@@ -46,7 +46,6 @@ struct settings {
 	uint32_t clock_quantum_floor;		/* quantum floor (lower bound) */
 	struct spa_rectangle video_size;
 	struct spa_fraction video_rate;
-	uint32_t link_min_buffers;
 	uint32_t link_max_buffers;
 	unsigned int mem_warn_mlock:1;
 	unsigned int mem_allow_mlock:1;

src/pipewire/settings.c

@@ -32,7 +32,6 @@
 #define DEFAULT_VIDEO_HEIGHT			480
 #define DEFAULT_VIDEO_RATE_NUM			25u
 #define DEFAULT_VIDEO_RATE_DENOM		1u
-#define DEFAULT_LINK_MIN_BUFFERS		2u
 #define DEFAULT_LINK_MAX_BUFFERS		64u
 #define DEFAULT_MEM_WARN_MLOCK			false
 #define DEFAULT_MEM_ALLOW_MLOCK			true
@@ -223,7 +222,6 @@ void pw_settings_init(struct pw_context *this)
 	d->log_level = get_default_int(p, "log.level", pw_log_level);
 	d->clock_power_of_two_quantum = get_default_bool(p, "clock.power-of-two-quantum",
 			DEFAULT_CLOCK_POWER_OF_TWO_QUANTUM);
-	d->link_min_buffers = get_default_int(p, "link.min-buffers", DEFAULT_LINK_MIN_BUFFERS);
 	d->link_max_buffers = get_default_int(p, "link.max-buffers", DEFAULT_LINK_MAX_BUFFERS);
 	d->mem_warn_mlock = get_default_bool(p, "mem.warn-mlock", DEFAULT_MEM_WARN_MLOCK);
 	d->mem_allow_mlock = get_default_bool(p, "mem.allow-mlock", DEFAULT_MEM_ALLOW_MLOCK);
@@ -231,8 +229,7 @@ void pw_settings_init(struct pw_context *this)
 	d->check_quantum = get_default_bool(p, "settings.check-quantum", DEFAULT_CHECK_QUANTUM);
 	d->check_rate = get_default_bool(p, "settings.check-rate", DEFAULT_CHECK_RATE);
 
-	d->link_min_buffers = SPA_MAX(d->link_min_buffers, 1u);
+	d->link_max_buffers = SPA_MAX(d->link_max_buffers, 1u);
-	d->link_max_buffers = SPA_MAX(d->link_max_buffers, d->link_min_buffers);
 
 	d->clock_quantum_limit = SPA_CLAMP(d->clock_quantum_limit,
 			CLOCK_QUANTUM_FLOOR, CLOCK_QUANTUM_LIMIT);