The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/7bafadd80653e2c380988db980884f5c7c370820

commit 7bafadd80653e2c380988db980884f5c7c370820
Author: paulhsia <paulhsia@chromium.org>
Date: Thu May 24 18:59:05 2018

[autotest] Select USB explicitly in USB test

In audio_AudioBasicUSBPlaybackRecord.suspend, some DUTs will detect MIC
again after suspend so MIC will become the main input node. The test is
for testing recording after suspend so it should check and select the node
explicitly.

Log down more information for future debuging.

BUG= chromium:846149 
TEST=test_that --fast --debug --args="chameleon_host=CHAMELEON_IP"
DUT_IP audio_AudioBasicUSBPlaybackRecord.suspend

Change-Id: I008ee182913791d6915b18a85deeff917a68d4d0
Reviewed-on: https://chromium-review.googlesource.com/1071127
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Chih-Yang Hsia <paulhsia@google.com>
Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>

[modify] https://crrev.com/7bafadd80653e2c380988db980884f5c7c370820/server/site_tests/audio_AudioBasicUSBPlaybackRecord/audio_AudioBasicUSBPlaybackRecord.py

This is a change only on test and the failure is in R67.
Need a approval for merging to R67.
Thanks!

This bug requires manual review: We are only 3 days from stable.
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), kbleicher@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Per #2, to confirm, this is only a test merge with no production impact?  I'd like to be sure since this is a late-stage merge request.  Thx

Yes, that is right. The only change  in +/1071127 is in the test itself, and it is not a bvt test, but OOB (post build).

Approving merge to M67 Chrome OS.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/2b4fc8d15c308fa868f09c14bb5003353337388b

commit 2b4fc8d15c308fa868f09c14bb5003353337388b
Author: paulhsia <paulhsia@chromium.org>
Date: Wed May 30 01:10:30 2018

[autotest] Select USB explicitly in USB test

In audio_AudioBasicUSBPlaybackRecord.suspend, some DUTs will detect MIC
again after suspend so MIC will become the main input node. The test is
for testing recording after suspend so it should check and select the node
explicitly.

Log down more information for future debuging.

BUG= chromium:846149 
TEST=test_that --fast --debug --args="chameleon_host=CHAMELEON_IP"
DUT_IP audio_AudioBasicUSBPlaybackRecord.suspend

Change-Id: I008ee182913791d6915b18a85deeff917a68d4d0
Previous-Reviewed-on: https://chromium-review.googlesource.com/1071127
(cherry picked from commit f6616c1719f489045262cb45c2191d39cd3df09f)
Reviewed-on: https://chromium-review.googlesource.com/1077712
Reviewed-by: Chih-Yang Hsia <paulhsia@chromium.org>
Commit-Queue: Chih-Yang Hsia <paulhsia@chromium.org>
Tested-by: Chih-Yang Hsia <paulhsia@chromium.org>

[modify] https://crrev.com/2b4fc8d15c308fa868f09c14bb5003353337388b/server/site_tests/audio_AudioBasicUSBPlaybackRecord/audio_AudioBasicUSBPlaybackRecord.py

The problem were fixed by the change and stable on those boards.
Please check from the following links:
https://stainless.corp.google.com/search?view=matrix&row=board_model&col=build&first_date=2018-05-13&last_date=2018-06-09&test=%5Eaudio%5C_AudioBasicUSBPlaybackRecord%5C.suspend%24&exclude_cts=true&exclude_not_run=false&exclude_non_release=true&exclude_au=true&exclude_acts=true&exclude_retried=true&exclude_non_production=false