[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] DeathKoil:
I believe I have narrowed down where the issue of some apps (google voice voicemail, grooveIP, likely many others) only using the external speaker stems from.

I took a logcat of listening to a voicemail in google voice on M1, and on the next nightly (Jan 21). I've attached "clean" versions of the logcats in which I removed unrelated data. These logs were taken after full wipes, with only GApps added so that I could download Google Voice from the Play store. Nothing else was added/changed.

The differences are in bold. It appears that as of the Jan 21 Nightly, and on every nightly after that, the sound driver doesn't even attempt to use the earpiece. It just goes right to the external speaker.

I wanted to submit a ticket on Jira about this, but it says to only report bugs that effect Monthly builds, Stable builds, and Release Candidate builds. This is a big issue for me since I use applications that are effect. Is there any other way to bring this information to the attention of the devs? All the info is right here. I've narrowed it down the the nightly it started at, and have a logcat showing why it isn't sending to the earpiece.

CM10.1-M1 build:

D/AwesomePlayer( 240): Tunnel Mime Type: audio/mpeg, object alive = 0, mTunnelAliveAP = 0
D/AwesomePlayer( 240): Normal Audio Playback
W/AwesomePlayer( 240): Trying to create tunnel player mIsTunnelAudio 0, LPAPlayer::objectsAlive 0, TunnelPlayer::mTunnelObjectsAlive = 0, (mAudioPlayer == NULL) 1
D/ALSAStreamOps( 240): setParameters(): keyRouting with device 0x1
D/ALSAStreamOps( 240): setParameters(): keyRouting with device 0x1
[B]D/ALSADevice( 240): route: devices 0x1 in mode 0[/B]
D/ALSADevice( 240): No valid input device: 0
[B]D/alsa_ucm( 240): snd_use_case_set(): uc_mgr 0x41f012e0 identifier _disdev value Speaker
D/alsa_ucm( 240): disdev: device Speaker not enabled, no need to disable
D/alsa_ucm( 240): snd_use_case_set(): uc_mgr 0x41f012e0 identifier _enadev value Earpiece
D/ALSADevice( 240): switchDevice: mCurTxUCMDevivce None mCurRxDevDevice Earpiece
I/ALSADevice( 240): a2220: txDevice=(null) rxDevice=Earpiece[/B]
D/ALSADevice( 240): route: devices 0x1 in mode 0
D/ALSADevice( 240): No valid input device: 0
D/alsa_ucm( 240): snd_use_case_set(): uc_mgr 0x41f012e0 identifier _verb value HiFi
[B]D/alsa_ucm( 240): Set mixer controls for Earpiece enable 1[/B]
D/alsa_ucm( 240): acdb_id 7 cap 1 enable 1

CM10.1 Jan21 Build:

D/AwesomePlayer( 240): Tunnel Mime Type: audio/mpeg, object alive = 0, mTunnelAliveAP = 0
D/AwesomePlayer( 240): Normal Audio Playback
W/AwesomePlayer( 240): Trying to create tunnel player mIsTunnelAudio 0, LPAPlayer::objectsAlive 0, TunnelPlayer::mTunnelObjectsAlive = 0, (mAudioPlayer == NULL) 1
[B]D/ALSADevice( 240): route: devices 0x2 in mode 0[/B]
D/ALSADevice( 240): No valid input device: 0
[B]D/alsa_ucm( 240): snd_use_case_set(): uc_mgr 0x400d3888 identifier _enadev value Speaker
D/ALSADevice( 240): switchDevice: mCurTxUCMDevivce None mCurRxDevDevice Speaker
I/ALSADevice( 240): a2220: txDevice=(null) rxDevice=Speaker[/B]
D/alsa_ucm( 240): snd_use_case_set(): uc_mgr 0x400d3888 identifier _verb value HiFi
[B]D/alsa_ucm( 240): Set mixer controls for Speaker enable 1[/B]
D/alsa_ucm( 240): acdb_id 15 cap 1 enable 1