doc: update with config overrides info

doc/pipewire-daemon.dox

@@ -62,8 +62,18 @@ for configuration files are:
 - `$sysconfdir/pipewire/pipewire.conf` (usually `/etc/pipewire/pipewire.conf`)
 - `$datadir/pipewire/pipewire.conf` (usually `/usr/share/pipewire/pipewire.conf`)
 
-The first configuration file found is loaded, the PipeWire daemon does not
-currently combine configuration files.
+The first configuration file found is loaded as the base configuration.
+
+Next, configuration sections are collected in the directories in this
+order:
+
+- `$datadir/pipewire/pipewire.conf.d/` (usually `/usr/share/pipewire/pipewire.conf.d/`)
+- `$sysconfdir/pipewire/pipewire.conf.d/` (usually `/etc/pipewire/pipewire.conf.d/`)
+- `$XDG_CONFIG_HOME/pipewire/pipewire.conf.d/` (usually `$HOME/.config/pipewire/pipewire.conf.d/`)
+
+They are applied to the global configuration file. Properties are overwritten
+and array elements are appended. This makes it possible to make small custom customizations
+or additions to the main configuration file.
 
 The environment variables `PIPEWIRE_CONFIG_DIR`, `PIPEWIRE_CONFIG_PREFIX`
 and `PIPEWIRE_CONFIG_NAME` can be used to specify an alternative config

man/pipewire.conf.5.rst.in

@@ -19,13 +19,19 @@ SYNOPSIS
 
 *@PIPEWIRE_CONFDATADIR@/pipewire.conf*
 
+*@PIPEWIRE_CONFDATADIR@/pipewire.conf.d/*
+
+*@PIPEWIRE_CONFIG_DIR@/pipewire.conf.d/*
+
+*$XDG_CONFIG_HOME/pipewire/pipewire.conf.d/*
+
 DESCRIPTION
 ===========
 
 PipeWire is a service that facilitates sharing of multimedia content
 between devices and applications.
 
-On startup, the daemon reads a configuration file to configure
+On startup, the daemon reads a main configuration file to configure
 itself. It executes a series of commands listed in the config
 file.
 
@@ -34,6 +40,13 @@ The environment variables ``PIPEWIRE_CONFIG_DIR``, ``PIPEWIRE_CONFIG_PREFIX``
 and ``PIPEWIRE_CONFIG_NAME`` can be used to specify an alternative config
 directory, subdirectory and file respectively.
 
+Next to the configuration file can be a directory with the same name as
+the file with a ``.d/`` suffix. All directories in the SYNOPSIS_ directory
+search paths are traversed in the listed order and the contents of the
+``*.conf`` files inside them are appended to the main configuration file
+as overrides. Object sections are merged and array sections are appended.
+
+
 CONFIGURATION FILE FORMAT
 =========================
 
@@ -51,6 +64,17 @@ name = [ value1 value2 ] # an array with two entries
 
 name = [ { k = v1 } { k = v2 } ] # an array of dictionaries
 
+
+The configuration files can be expressed in full JSON syntax but for ease
+of use, a relaxed format may be used where:
+
+ * ``:`` to delimit keys and values can be substuted by ``=`` or a space.
+ * ``"`` around keys and string can be omited as long as no special characters
+         are used in the strings.
+ * ``,`` to separate objects can be replaced with a whitespace character.
+ * ``#`` can be used to start a comment until the line end
+
+
 CONFIGURATION FILE SECTIONS
 ===========================
 

src/daemon/client-rt.conf.in

@@ -2,6 +2,11 @@
 #
 # Copy and edit this file in @PIPEWIRE_CONFIG_DIR@ for system-wide changes
 # or in ~/.config/pipewire for local changes.
+#
+# It is also possible to place a file with an updated section in
+# @PIPEWIRE_CONFIG_DIR@/client-rt.conf.d/ for system-wide changes or in
+# ~/.config/pipewire/client-rt.conf.d/ for local changes.
+#
 
 context.properties = {
     ## Configure properties in the system.

src/daemon/client.conf.in

@@ -2,7 +2,11 @@
 #
 # Copy and edit this file in @PIPEWIRE_CONFIG_DIR@ for system-wide changes
 # or in ~/.config/pipewire for local changes.
-
+#
+# It is also possible to place a file with an updated section in
+# @PIPEWIRE_CONFIG_DIR@/client.conf.d/ for system-wide changes or in
+# ~/.config/pipewire/client.conf.d/ for local changes.
+#
 context.properties = {
     ## Configure properties in the system.
     #mem.warn-mlock  = false

src/daemon/jack.conf.in

@@ -2,6 +2,11 @@
 #
 # Copy and edit this file in @PIPEWIRE_CONFIG_DIR@ for system-wide changes
 # or in ~/.config/pipewire for local changes.
+#
+# It is also possible to place a file with an updated section in
+# @PIPEWIRE_CONFIG_DIR@/jack.conf.d/ for system-wide changes or in
+# ~/.config/pipewire/jack.conf.d/ for local changes.
+#
 
 context.properties = {
     ## Configure properties in the system.

src/daemon/minimal.conf.in

@@ -2,6 +2,11 @@
 #
 # Copy and edit this file in @PIPEWIRE_CONFIG_DIR@ for system-wide changes
 # or in ~/.config/pipewire for local changes.
+#
+# It is also possible to place a file with an updated section in
+# @PIPEWIRE_CONFIG_DIR@/minimal.conf.d/ for system-wide changes or in
+# ~/.config/pipewire/minimal.conf.d/ for local changes.
+#
 
 context.properties = {
     ## Configure properties in the system.

src/daemon/pipewire-pulse.conf.in

@@ -2,6 +2,11 @@
 #
 # Copy and edit this file in @PIPEWIRE_CONFIG_DIR@ for system-wide changes
 # or in ~/.config/pipewire for local changes.
+#
+# It is also possible to place a file with an updated section in
+# @PIPEWIRE_CONFIG_DIR@/pipewire-pulse.conf.d/ for system-wide changes or in
+# ~/.config/pipewire/pipewire-pulse.conf.d/ for local changes.
+#
 
 context.properties = {
     ## Configure properties in the system.

src/daemon/pipewire.conf.in

@@ -2,6 +2,11 @@
 #
 # Copy and edit this file in @PIPEWIRE_CONFIG_DIR@ for system-wide changes
 # or in ~/.config/pipewire for local changes.
+#
+# It is also possible to place a file with an updated section in
+# @PIPEWIRE_CONFIG_DIR@/pipewire.conf.d/ for system-wide changes or in
+# ~/.config/pipewire/pipewire.conf.d/ for local changes.
+#
 
 context.properties = {
     ## Configure properties in the system.
@@ -24,7 +29,7 @@ context.properties = {
     #default.clock.rate          = 48000
     #default.clock.allowed-rates = [ 48000 ]
     #default.clock.quantum       = 1024
-    #default.clock.min-quantum   = 32
+    default.clock.min-quantum   = 16
     #default.clock.max-quantum   = 2048
     #default.clock.quantum-limit = 8192
     #default.video.width         = 640