title: Inject uplink audio in call with Snapdragon MSM8960 SoC
body: <p>I've been investigating on this topic specific to MSM8960 for some time. I looked into the <a href="https://android.googlesource.com/platform/hardware/qcom/audio/+/master" rel="nofollow noreferrer">ALSA hardware module from google</a>. Michael's answer in the <a href="https://stackoverflow.com/questions/10544992/call-audio-stream-modification-in-android-4-0-ics">post</a> did mention that MSM8960 supported the in-call uplink audio injection at "Hardware and Device Driver" level. Did it refer to the level at this ALSA module?</p>
  
  <p>From the ALSA config file on the phone, it seems the in call voice playback is done through <code>/dev/snd/pcmC0D0p</code>, or at least comply with the ALSA paradigm. Is it possible to play with one of the file descriptor to achieve the purpose? I do see some interesting USE_CASE definition in libalsa-intf.</p>