meta-digi-dey: pulseaudio: load HDMI sink on hotplug

When hotplugging the HDMI cable after booting the target, pulseaudio doesn't
load the HDMI sink. This commit fixes this by adding a udev rule and a script
that prompts pulseaudio to detect the HDMI sound card and load its sink, as
well as making it the default one.

If alsa-utils is available, a faulty command is run to load the card without
any audio output. Otherwise, module-udev-detect is unloaded and reloaded.

This is based on commit fca507d316.

https://jira.digi.com/browse/DEL-2327

Signed-off-by: Gabriel Valcazar <gabriel.valcazar@digi.com>

meta-digi-dey/recipes-multimedia/pulseaudio/pulseaudio/hdmi_hotplug.sh

@@ -0,0 +1,44 @@
+#!/bin/sh
+#===============================================================================
+#
+#  hdmi_hotplug.sh
+#
+#  Copyright (C) 2017 by Digi International Inc.
+#  All rights reserved.
+#
+#  This program is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU General Public License version 2 as published by
+#  the Free Software Foundation.
+#
+#
+#  !Description: HDMI hotplug script called from udev on HDMI plug/unplug event
+#
+#===============================================================================
+
+# Find HDMI card number
+for card in /sys/class/sound/card*; do
+	if readlink "${card}/device" | grep -qs hdmi; then
+		HDMI_CARD="${card##/sys/class/sound/card}"
+		break
+	fi
+done
+
+# On HDMI plugin event, if the sink has not been loaded yet, load the
+# HDMI audio sink from ALSA
+if [ "${EVENT}" = "plugin" ]; then
+	if ! pactl list sinks | grep -qs "imx-hdmi-soc"; then
+		if which aplay; then
+			# Run a command that always fails but loads
+			# pulseaudio HDMI sink/card as a side effect
+			aplay / -D "hw:${HDMI_CARD}"
+ 		else
+			# Unload and reload the detection module
+			pactl unload-module module-udev-detect
+			pactl load-module module-udev-detect tsched=0
+		fi
+
+		# Set HDMI as default sink
+		pactl set-default-sink "$(pactl list sinks | grep -i 'Name:.*hdmi' | cut -d ' ' -f2)"
+	fi
+fi
+

meta-digi-dey/recipes-multimedia/pulseaudio/pulseaudio_%.bbappend

@@ -3,5 +3,16 @@
 FILESEXTRAPATHS_prepend := "${THISDIR}/${BPN}:"
 
 SRC_URI_append_ccimx6ulsbc = " file://0001-pulseaudio-keep-headphones-volume-in-platforms-witho.patch"
+SRC_URI_append_ccimx6sbc = " file://hdmi_hotplug.sh"
+
+do_install_append_ccimx6sbc() {
+	install -d ${D}${sysconfdir}/udev/scripts
+	install -m 0755 ${WORKDIR}/hdmi_hotplug.sh ${D}${sysconfdir}/udev/scripts
+
+	cat >> ${D}${base_libdir}/udev/rules.d/90-pulseaudio.rules <<-_EOL_
+
+		SUBSYSTEM=="platform", KERNEL=="*hdmi_video", ACTION=="change", RUN+="/etc/udev/scripts/hdmi_hotplug.sh"
+	_EOL_
+}
 
 PACKAGE_ARCH = "${MACHINE_ARCH}"