一般不加contents参数会直观些。
好像我这个帖子里面最后那部分显示那样。
Simple mixer control ‘Master’,0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback 0 - 74
Mono: Playback 54 [73%] [-20.00dB] [on]
Simple mixer control ‘Headphone’,0
Capabilities: pvolume pswitch
Playback channels: Front Left - Front Right
Limits: Playback 0 - 74
Mono:
Front Left: Playback 74 [100%] [0.00dB] [on]
Front Right: Playback 74 [100%] [0.00dB] [on]
Simple mixer control ‘Speaker’,0
Capabilities: pvolume pswitch
Playback channels: Front Left - Front Right
Limits: Playback 0 - 74
Mono:
Front Left: Playback 74 [100%] [0.00dB] [on]
Front Right: Playback 74 [100%] [0.00dB] [on]
Simple mixer control ‘Mic Boost’,0
Capabilities: volume
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]