Allow running check_audio.py without root

Running as root means that ALSA ignores /home/pi/.asoundrc, so problems
with the demos can't (easily) be detected in check_audio.py. See:
#254

Since it now uses configure_driver.sh, we have to fix
#268
or the config will not survive a reboot.

Change-Id: Icb440243395d885f20cd345b57a83ed82edd6e71

checkpoints/check_audio.py

@@ -19,6 +19,7 @@
 import fileinput
 import os
 import re
+import subprocess
 import sys
 import tempfile
 import textwrap
@@ -137,15 +138,10 @@ def do_checks():
 
 
 def enable_audio_driver():
-    print(textwrap.fill(
-        """Enabling audio driver for VoiceKit."""))
-    for line in fileinput.input("/boot/config.txt",
-                                inplace=True, backup=".bak"):
-        if re.match("^# dtoverlay=googlevoicehat-soundcard", line):
-            print("dtoverlay=googlevoicehat-soundcard")
-        else:
-            print(line, end='')
-    os.system("dtoverlay googlevoicehat-soundcard")
+    print("Enabling audio driver for VoiceKit.")
+    configure_driver = os.path.join(
+        os.path.dirname(__file__), '..', 'scripts', 'configure-driver.sh')
+    subprocess.check_call(['sudo', configure_driver])
 
 
 def main():

scripts/configure-driver.sh

@@ -25,7 +25,9 @@ set -e
 
 sed -i \
   -e "s/^dtparam=audio=on/#\0/" \
-  -e "s/^#\(dtparam=i2s=on\)/\1/" \
+  -e "s/^#\s*\(dtparam=i2s=on\)/\1/" \
+  -e "s/^#\s*\(dtoverlay=i2s-mmap\)/\1/" \
+  -e "s/^#\s*\(dtoverlay=googlevoicehat-soundcard\)/\1/" \
   /boot/config.txt
 grep -q "dtoverlay=i2s-mmap" /boot/config.txt || \
   echo "dtoverlay=i2s-mmap" >> /boot/config.txt
@@ -34,3 +36,4 @@ grep -q "dtoverlay=googlevoicehat-soundcard" /boot/config.txt || \
 grep -q "dtparam=i2s=on" /boot/config.txt || \
   echo "dtparam=i2s=on" >> /boot/config.txt
 
+dtoverlay googlevoicehat-soundcard

shortcuts/check_audio.desktop

@@ -3,5 +3,5 @@ Encoding=UTF-8
 Type=Application
 Name=Check audio
 Comment=Check that the voiceHAT audio input and output are both working.
-Exec=sudo /home/pi/AIY-projects-python/env/bin/python /home/pi/AIY-projects-python/checkpoints/check_audio.py
+Exec=/home/pi/AIY-projects-python/env/bin/python /home/pi/AIY-projects-python/checkpoints/check_audio.py
 Terminal=true