CHROMIUM: ALSA: hda: manage EAPD timing to remove audible 'pop' on Alex speakers

For systems with external amplifiers the EAPD signal can be used to
turn on/off the amp.  Depending upon the amplifier used in the system
this signal can lead to audible popping on EAPD assert/de-assert.  This
change aims to mitigate the popping by enabling (resuming) EAPD after
inputs to the amplifier have setup.  On disable (suspend) it allows
EAPD to proceed disabling of amp inputs.

BUG=chrome-os-partner:3971
TEST=manual, on CR-48 and other partner systems w/ this codec using
alex_pop.sh script posted on tracker.  Additionally played audio via
html5zombo.com across suspend / resume cycles.

Change-Id: I3c7f7b71b72c9e8540f3118119c000c572eef62c
Signed-off-by: Todd Broch <tbroch@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/2487
Reviewed-by: Olof Johansson <olofj@chromium.org>
Reviewed-by: Puneet Kumar <puneetster@chromium.org>
1 file changed