[参考译文] PROCESSOR-SDK-J784S4：如何使用 amixer 命令控制卷

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请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1480088/processor-sdk-j784s4-how-to-control-the-volume-using-amixer-command

器件型号：PROCESSOR-SDK-J784S4

工具与软件：

大家好、团队成员：

我们正在尝试将音频用于我们的定制电路板。我们使用虚拟编解码器。

对我们来说、游戏和娱乐都很好。

root@j784s4-evm:~# aplay -Dplughw:0,0 c304-2.wav
Playing WAVE 'c304-2.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
^CAborted by signal Interrupt...
root@j784s4-evm:~# arecord -Dplughw:0,0 -c 2 -r 48000 -f S16_LE test.wav
Recording WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
^CAborted by signal Interrupt...
root@j784s4-evm:~#

但是,当我们尝试使用 amixer 命令来设置卷时,我们会收到以下错误。

root@j784s4-evm:~# amixer -Dplughw:0,0 sset J784S4-TEST 50%
ALSA lib /usr/src/debug/alsa-lib/1.2.11/src/control/control.c:1570:(snd_ctl_open_noupdate) Invalid CTL plughw:0,0
amixer: Mixer attach plughw:0,0 error: No such file or directory

如何使用 amixer 命令设置卷

root@j784s4-evm:~# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: J784S4TEST [J784S4-TEST], device 0: 2b00000.mcasp-snd-soc-dummy-dai snd-soc-dummy-dai-0 [2b00000.mcasp-snd-soc-dummy-dai snd-soc-dummy-dai-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: J784S4TEST_1 [J784S4-TEST], device 0: 2b10000.mcasp-snd-soc-dummy-dai snd-soc-dummy-dai-0 [2b10000.mcasp-snd-soc-dummy-dai snd-soc-dummy-dai-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: J784S4TEST_2 [J784S4-TEST], device 0: 2b30000.mcasp-snd-soc-dummy-dai snd-soc-dummy-dai-0 [2b30000.mcasp-snd-soc-dummy-dai snd-soc-dummy-dai-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

此致

Ajins

8 个月前

0 admin 8 个月前

TI__Guru**** 2457760 points

请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

Ajins、您好！

您使用 amixer 引用了错误的器件名称。您应该参考该卡、或者将设备作为`hw:N`、其中 N 是指定的卡号(amixer 手册页)。

您可以使用以下两个命令之一将音量设置为70%：

$ amixer -c0 sset 'codec-1 DAC1' 70%
$ amixer -Dhw:0 sset 'codec-1 DAC1' 70%

您可以使用以下命令查看可控设置：

$ amixer -c0

测试对象：

$ aplay -Dplughw:0,0 /dev/random

此致！
Jared

0 admin 8 个月前

TI__Guru**** 2457760 points

请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

尊敬的 Jared：

amixer -c0未列出任何内容。

我们使用虚拟编解码器。如何找到相应的控件？

此致

Ajins

0 admin 8 个月前

TI__Guru**** 2457760 points

请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

Ajins、您好！

是否可以发送设备树？

此致！
Jared

0 admin 8 个月前

TI__Guru**** 2457760 points

请注意，本文内容源自机器翻译，可能存在语法或其它翻译错误，仅供参考。如需获取准确内容，请参阅链接中的英语原文或自行翻译。

Ajins、您好！

amixer 的控件来自编解码器驱动程序。例如、如果您在 pcm3168a 驱动程序( k3-j784s4-evm.dts 中使用的编解码器)中查看、您将看到 amixer 列出的所有设置：

root@j784s4-evm:~# amixer -c0
Simple mixer control 'codec-1 ADC Overflow Flag Polarity',0
  Capabilities: enum
  Items: 'Active High' 'Active Low'
  Item0: 'Active High'
Simple mixer control 'codec-1 ADC Volume Control Type',0
  Capabilities: enum
  Items: 'Individual' 'Master + Individual'
  Item0: 'Individual'
Simple mixer control 'codec-1 ADC Volume Rate Multiplier',0
  Capabilities: enum
  Items: '2048' '4096'
  Item0: '2048'
Simple mixer control 'codec-1 ADC1',0
  Capabilities: cvolume
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 241
  Front Left: Capture 197 [82%] [-2.00dB]
  Front Right: Capture 197 [82%] [-2.00dB]
Simple mixer control 'codec-1 ADC1 Connection Type',0
  Capabilities: enum
  Items: 'Differential' 'Single-Ended'
  Item0: 'Differential'
  Item1: 'Differential'
Simple mixer control 'codec-1 ADC1 High-Pass Filter',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'codec-1 ADC1 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 ADC1 Mute',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 ADC2',0
  Capabilities: cvolume
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 241
  Front Left: Capture 197 [82%] [-2.00dB]
  Front Right: Capture 197 [82%] [-2.00dB]
Simple mixer control 'codec-1 ADC2 Connection Type',0
  Capabilities: enum
  Items: 'Differential' 'Single-Ended'
  Item0: 'Differential'
  Item1: 'Differential'
Simple mixer control 'codec-1 ADC2 High-Pass Filter',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'codec-1 ADC2 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 ADC2 Mute',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 ADC3',0
  Capabilities: cvolume
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 241
  Front Left: Capture 197 [82%] [-2.00dB]
  Front Right: Capture 197 [82%] [-2.00dB]
Simple mixer control 'codec-1 ADC3 Connection Type',0
  Capabilities: enum
  Items: 'Differential' 'Single-Ended'
  Item0: 'Differential'
  Item1: 'Differential'
Simple mixer control 'codec-1 ADC3 High-Pass Filter',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'codec-1 ADC3 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 ADC3 Mute',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 DAC De-Emphasis',0
  Capabilities: enum
  Items: 'Disabled' '48khz' '44.1khz' '32khz'
  Item0: 'Disabled'
Simple mixer control 'codec-1 DAC Power-Save',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'codec-1 DAC Volume Control Type',0
  Capabilities: enum
  Items: 'Individual' 'Master + Individual'
  Item0: 'Individual'
Simple mixer control 'codec-1 DAC Volume Rate Multiplier',0
  Capabilities: enum
  Items: '2048' '4096'
  Item0: '2048'
Simple mixer control 'codec-1 DAC Zero Flag Function',0
  Capabilities: enum
  Items: 'DAC 1/2/3/4 AND' 'DAC 1/2/3/4 OR' 'DAC 1/2/3 AND' 'DAC 1/2/3 OR' 'DAC 4 AND' 'DAC 4 OR'
  Item0: 'DAC 1/2/3/4 AND'
Simple mixer control 'codec-1 DAC Zero Flag Polarity',0
  Capabilities: enum
  Items: 'Active High' 'Active Low'
  Item0: 'Active High'
Simple mixer control 'codec-1 DAC1',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 201
  Mono:
  Front Left: Playback 201 [100%] [0.00dB]
  Front Right: Playback 201 [100%] [0.00dB]
Simple mixer control 'codec-1 DAC1 Digital Filter roll-off',0
  Capabilities: enum
  Items: 'Sharp' 'Slow'
  Item0: 'Sharp'
Simple mixer control 'codec-1 DAC1 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 DAC2',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 201
  Mono:
  Front Left: Playback 201 [100%] [0.00dB]
  Front Right: Playback 201 [100%] [0.00dB]
Simple mixer control 'codec-1 DAC2 Digital Filter roll-off',0
  Capabilities: enum
  Items: 'Sharp' 'Slow'
  Item0: 'Sharp'
Simple mixer control 'codec-1 DAC2 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 DAC3',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 201
  Mono:
  Front Left: Playback 201 [100%] [0.00dB]
  Front Right: Playback 201 [100%] [0.00dB]
Simple mixer control 'codec-1 DAC3 Digital Filter roll-off',0
  Capabilities: enum
  Items: 'Sharp' 'Slow'
  Item0: 'Sharp'
Simple mixer control 'codec-1 DAC3 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 DAC4',0
  Capabilities: pvolume
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 201
  Mono:
  Front Left: Playback 201 [100%] [0.00dB]
  Front Right: Playback 201 [100%] [0.00dB]
Simple mixer control 'codec-1 DAC4 Digital Filter roll-off',0
  Capabilities: enum
  Items: 'Sharp' 'Slow'
  Item0: 'Sharp'
Simple mixer control 'codec-1 DAC4 Invert',0
  Capabilities: pswitch
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [off]
  Front Right: Playback [off]
Simple mixer control 'codec-1 Master',0
  Capabilities: pvolume pvolume-joined cvolume cvolume-joined
  Playback channels: Mono
  Capture channels: Mono
  Limits: Playback 0 - 201 Capture 0 - 241
  Mono: Playback 201 [100%] [0.00dB] Capture 197 [82%] [-2.00dB]

SND-SND-Dummy soc 编解码器不是真正的编解码器、也没有任何控制。因此、您无法在 amixer 中设置音量。

此致！
Jared

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[参考译文] PROCESSOR-SDK-J784S4：如何使用 amixer 命令控制卷