我正在尝试配置插入 Raspberry Pi 3 的 USB 麦克风并运行树莓派杰西。
在对系统进行任何更改之前，我常常检查普通用户和超级用户的amixer情况：piroot
$ amixer
Simple mixer control 'PCM',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -1926 [78%] [-19.26dB] [on]
$ sudo amixer
Simple mixer control 'PCM',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -1926 [78%] [-19.26dB] [on]
然后，我将以下行放入文件中/etc/modprobe.d/alsa-base.conf以将麦克风的声卡修复在索引 0 处：
options snd_usb_audio index=0
options snd_bcm2835 index=1
options snd slots=snd_usb_audio,snd_bcm2835
重新启动后，我曾经amixer再次检查情况，对于pi和root：
$ amixer
Simple mixer control 'PCM',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -1925 [78%] [-19.25dB] [on]
$ sudo amixer
Simple mixer control 'Mic',0
Capabilities: cvolume cvolume-joined cswitch cswitch-joined
Capture channels: Mono
Limits: Capture 0 - 16
Mono: Capture 8 [50%] [11.90dB] [on]
Simple mixer control 'Auto Gain Control',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [on]
为什么他们变得不一样了？似乎root已经采用了新配置，但pi实际上还没有。我怎样才能让它们再次相同？这里发生了什么？