tree 830b862336be7fed8826bc6136671a1369f21b4c
parent d2977c83341f8491e03dc69a9940cef713b44309
author Eric Laurent <elaurent@google.com> 1334361497 -0700
committer Eric Laurent <elaurent@google.com> 1335834340 -0700

audio: add support for deep PCM buffering

Implement one output stream with short buffers and
one output stream with deep buffers.
The stream with short buffers is selected for most use cases and
provides short latency. It uses TONES_DL port and IOCTL write mode.
The stream with deep buffers is used for music playback.
It uses MM_DL port and MMAP NOIRQ write mode.

The deep buffer stream is not used when the device selection is
BT SCO, HDMI or SPDIF.
The echo reference is only taken from the short buffer stream.

Change-Id: I60ef720e52e96970b8b6618f9f43f24baadce60b