The issue is reproduced separately for audio jack and USB audio peripherals.

HDMI audio is functioning as expected(after display is extended/mirrored).

When plugged USB and headphones together while DUT is off(after powerwash), the output node was set on Headphone(3.5) and input node on Internal Mic, which might be effect of a bigger issue.

This issue is observed on M52-BETA-6 (8350.38.0) 52.0.2743.49 too with all DUTs.

#CBC-RS/TC-watchlist

May be related to CBC reference: https://productforums.google.com/forum/#!topic/chromebook-central/40yPz2UCxsA

I could repro this case on samus, am looking into it.

This is a corner case that a new audio device is plugged in for the first on a cros device after the device is powered down. After reboot, the old active device(internal speaker) is selected as the active one from the previously saved audio prefs. Another repro case would be.
1. Install a new image on a cros device with internal speaker but no other audio output attached.
2. Power down.
3. Plug in headphone.
4. Power on.
Result: The internal speaker is selected as active.

I have a pending cl to fix this issue. For such corner case, instead of honoring the active device from the previous session, re-select the active device by priority, which is likely the best bet for such corner case.

https://codereview.chromium.org/2189463004/

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87

commit 6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87
Author: jennyz <jennyz@chromium.org>
Date: Thu Jul 28 17:49:11 2016

Fix the corner case for new audio device is not selected as active if it is plugged in for the first time after cros device is powered down.

BUG= 622045 

Review-Url: https://codereview.chromium.org/2189463004
Cr-Commit-Position: refs/heads/master@{#408431}

[modify] https://crrev.com/6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87/chromeos/audio/audio_devices_pref_handler_impl.cc
[modify] https://crrev.com/6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87/chromeos/audio/audio_devices_pref_handler_impl_unittest.cc
[modify] https://crrev.com/6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87/chromeos/audio/cras_audio_handler.cc
[modify] https://crrev.com/6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87/chromeos/audio/cras_audio_handler_unittest.cc

Fixed on TOT.

 Issue 597130  has been merged into this issue.

Your change meets the bar and is auto-approved for M53 (branch: 2785)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/526139a9551af8525f74ee05c406ec62f4f1a98d

commit 526139a9551af8525f74ee05c406ec62f4f1a98d
Author: Jenny Zhang <jennyz@chromium.org>
Date: Tue Aug 23 17:33:16 2016

Fix the corner case for new audio device is not selected as active if it is plugged in for the first time after cros device is powered down.

BUG= 622045 

Review-Url: https://codereview.chromium.org/2189463004
Cr-Commit-Position: refs/heads/master@{#408431}
(cherry picked from commit 6d5579b510fe8dcc6efb7ea1b6e881f840aa7f87)

Review URL: https://codereview.chromium.org/2270693005 .

Cr-Commit-Position: refs/branch-heads/2785@{#726}
Cr-Branched-From: 68623971be0cfc492a2cb0427d7f478e7b214c24-refs/heads/master@{#403382}

[modify] https://crrev.com/526139a9551af8525f74ee05c406ec62f4f1a98d/chromeos/audio/audio_devices_pref_handler_impl.cc
[modify] https://crrev.com/526139a9551af8525f74ee05c406ec62f4f1a98d/chromeos/audio/audio_devices_pref_handler_impl_unittest.cc
[modify] https://crrev.com/526139a9551af8525f74ee05c406ec62f4f1a98d/chromeos/audio/cras_audio_handler.cc
[modify] https://crrev.com/526139a9551af8525f74ee05c406ec62f4f1a98d/chromeos/audio/cras_audio_handler_unittest.cc

verified in 8743.8.0, 54.0.2840.10