dsm_calibration
===============
**Source code:** `dsm_calibration.py <https://chromium.googlesource.com/chromiumos/platform/factory/+/refs/heads/main/py/test/pytests/dsm_calibration.py>`_

A factory test to calibrate the smart speaker amplifier.

Description
-----------
The test calibrates the smart speaker amplifier by following steps::

  1. Play silent music to load DSM module.
  2. Enter calibration mode.
  3. Wait for 3 seconds to get stable Rdc.
  4. Read Rdc values from two speakers.
  5. Store result to VPD.
  6. Quit calibration mode.

After this test, it is recommended to run ``RebootStep`` to load calibration
data into cras, and run ``SpeakerDMic`` test to verify the calibration result.

This test only works for some smart speaker amplifiers because some vendors
don't want to share their software to public.

Test Procedure
--------------
This is an automated test without user interaction.

Dependency
----------
- ``alsactl-tlv``
- Device API ``cros.factory.device.audio``.
- Device API ``cros.factory.device.vpd``.

Examples
--------
To calibrate the speaker device hw:1,0, add this into test list:

.. test_list::

  generic_audio_examples:AudioTests.DSMCalibration

See `audio_loop.py <./audio_loop.html>`_ for more details about how to set
``output_dev``.


Test Arguments
--------------
.. list-table::
   :widths: 20 10 60
   :header-rows: 1
   :align: left

   * - Name
     - Type
     - Description

   * - output_dev
     - list
     - (optional; default: ``['0', '0']``) Output ALSA device. [card_name, sub_device].For example: ["audio_card", "0"].

   * - num_output_channels
     - int
     - (optional; default: ``2``) Number of output channels.