asound.conf is different between 2mic and 4mic

asound_2mic.conf

@@ -1,11 +1,11 @@
 # The IPC key of dmix or dsnoop plugin must be unique
 # If 555555 or 666666 is used by other processes, use another one
 
-# pcm.!default {
-#     type asym
-#     playback.pcm "playback"
-#     capture.pcm "capture"
-# }
+pcm.!default {
+    type asym
+    playback.pcm "playback"
+    capture.pcm "capture"
+}
 
 pcm.playback {
     type plug
@@ -32,8 +32,3 @@ pcm.array {
     ipc_key 666666
 }
 
-pcm.ac108 {
-        type ac108
-        slavepcm "hw:1,0"
-        channels 4
-}

asound_4mic.conf

@@ -0,0 +1,27 @@
+# The IPC key of dmix or dsnoop plugin must be unique
+# If 555555 or 666666 is used by other processes, use another one
+
+pcm.!default {
+    type asym
+    playback.pcm "playback"
+    capture.pcm "ac108"
+}
+
+pcm.playback {
+    type plug
+    slave.pcm "dmixed"
+}
+
+
+pcm.dmixed {
+    type dmix
+    slave.pcm "hw:0,0"
+    ipc_key 555555 
+}
+
+
+pcm.ac108 {
+        type ac108
+        slavepcm "hw:1,0"
+        channels 4
+}

install.sh

@@ -56,7 +56,6 @@ if [ ! -f "/boot/overlays/seeed-4mic-voicecard.dtbo" ] && [ ! -f "/lib/modules/$
   cp seeed-2mic-voicecard.dtbo /boot/overlays
   cp seeed-4mic-voicecard.dtbo /boot/overlays
   cp ac108_plugin/libasound_module_pcm_ac108.so   /usr/lib/arm-linux-gnueabihf/alsa-lib/  
-  cp asound.conf /etc/
 else
   echo "card driver already installed"
 fi
@@ -80,6 +79,7 @@ case "${card}" in
    "2mic") 
     echo "cp wm8960_asound.state /var/lib/alsa/asound.state"
     cp wm8960_asound.state /var/lib/alsa/asound.state
+    cp asound_2mic.conf /etc/asound.conf
     if [ "x${has_4mic}" != x ] ; then
       echo "has 4mic before, now remove it"
       sed -i "s/dtoverlay=seeed-4mic-voicecard//g" /boot/config.txt
@@ -91,6 +91,7 @@ case "${card}" in
    "4mic") 
     echo "cp ac108_asound.state /var/lib/alsa/asound.state"
     cp ac108_asound.state /var/lib/alsa/asound.state
+    cp asound_4mic.conf /etc/asound.conf
     if [ "x${has_2mic}" != x ] ; then
       echo "has 2mic before, now remove it"
       sed -i "s/dtoverlay=seeed-2mic-voicecard//g" /boot/config.txt

uninstall.sh

@@ -43,6 +43,11 @@ if [ x${card} = "x2mic" ] ; then
 		echo  "remove wm8960_asound.state"
 		rm /var/lib/alsa/asound.state
 	fi
+
+	if [ -f /etc/asound.conf ] ; then
+        echo  "remove asound_2mic.conf"
+        rm /etc/asound.conf
+	fi	
 fi
 
 if [ x${card} = "x4mic" ] ; then
@@ -72,6 +77,11 @@ if [ x${card} = "x4mic" ] ; then
         rm /var/lib/alsa/asound.state
 	fi
 
+	if [ -f /etc/asound.conf ] ; then
+        echo  "remove asound_4mic.conf"
+        rm /etc/asound.conf
+	fi
+
 	if [ -f /usr/lib/arm-linux-gnueabihf/alsa-lib/libasound_module_pcm_ac108.so ] ; then
 		echo "remove libasound_module_pcm_ac108.so in /usr/lib/arm-linux-gnueabihf/alsa-lib/ "
 		rm  /usr/lib/arm-linux-gnueabihf/alsa-lib/libasound_module_pcm_ac108.so