$ amixer
Simple mixer control 'Master',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 31
  Mono: Playback 0 [0%] [0.00dB] [on]
Simple mixer control 'Headphone',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 31 [100%] [0.00dB] [on]
  Front Right: Playback 31 [100%] [0.00dB] [on]
Simple mixer control 'PCM',0
  Capabilities: pvolume penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 255
  Mono:
  Front Left: Playback 61 [24%] [-38.80dB]
  Front Right: Playback 61 [24%] [-38.80dB]
Simple mixer control 'Front',0
  Capabilities: pswitch penum
  Playback channels: Front Left - Front Right
  Mono:
  Front Left: Playback [on]
  Front Right: Playback [on]
Simple mixer control 'Front Mic',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 0 [0%] [-34.50dB] [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off]
Simple mixer control 'Front Mic Boost',0
  Capabilities: volume penum
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: 0 - 3
  Front Left: 0 [0%] [0.00dB]
  Front Right: 0 [0%] [0.00dB]
Simple mixer control 'Surround',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 31 [100%] [0.00dB] [on]
  Front Right: Playback 31 [100%] [0.00dB] [on]
Simple mixer control 'Center',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 31
  Mono: Playback 31 [100%] [0.00dB] [on]
Simple mixer control 'LFE',0
  Capabilities: pvolume pvolume-joined pswitch pswitch-joined penum
  Playback channels: Mono
  Limits: Playback 0 - 31
  Mono: Playback 31 [100%] [0.00dB] [on]
Simple mixer control 'Line',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 31 [100%] [12.00dB] [on]
  Front Right: Playback 31 [100%] [12.00dB] [on]
Simple mixer control 'IEC958',0
  Capabilities: pswitch pswitch-joined cswitch cswitch-joined penum
  Playback channels: Mono
  Capture channels: Mono
  Mono: Playback [on] Capture [off]
Simple mixer control 'IEC958 Default PCM',0
  Capabilities: pswitch pswitch-joined penum
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'IEC958',1
  Capabilities: pswitch pswitch-joined penum
  Playback channels: Mono
  Mono: Playback [on]
Simple mixer control 'Capture',0
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 31
  Front Left: Capture 19 [61%] [12.00dB] [on]
  Front Right: Capture 19 [61%] [12.00dB] [on]
Simple mixer control 'Capture',1
  Capabilities: cvolume cswitch penum
  Capture channels: Front Left - Front Right
  Limits: Capture 0 - 31
  Front Left: Capture 0 [0%] [-16.50dB] [off]
  Front Right: Capture 0 [0%] [-16.50dB] [off]
Simple mixer control 'Auto-Mute Mode',0
  Capabilities: enum
  Items: 'Disabled' 'Enabled'
  Item0: 'Disabled'
Simple mixer control 'Input Source',0
  Capabilities: cenum
  Items: 'Rear Mic' 'Front Mic' 'Line'
  Item0: 'Front Mic'
Simple mixer control 'Input Source',1
  Capabilities: cenum
  Items: 'Rear Mic' 'Front Mic' 'Line'
  Item0: 'Rear Mic'
Simple mixer control 'Rear Mic',0
  Capabilities: pvolume pswitch penum
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 31
  Mono:
  Front Left: Playback 0 [0%] [-34.50dB] [off]
  Front Right: Playback 0 [0%] [-34.50dB] [off]
Simple mixer control 'Rear Mic Boost',0
  Capabilities: volume penum
  Playback channels: Front Left - Front Right
  Capture channels: Front Left - Front Right
  Limits: 0 - 3
  Front Left: 0 [0%] [0.00dB]
  Front Right: 0 [0%] [0.00dB]