我正在运行运行 ubuntu 16.0.4 LTS 的嵌入式硬件的游戏应用程序。
我想删除 pulseaudio 模块并直接从我们的应用程序使用 ALSA。
我pulseaudio使用以下命令删除了：
sudo apt-get --purge remove pulseaudio
之后我重新启动了系统，让 ALSA 接管作为没有 pulseaudio 的默认声音系统。
列出的声卡/proc/asound/cards为：
0 [HDMI ]: HDA-Intel - HDA Intel HDMI
HDA Intel HDMI at 0xf7430000 irq 33
1 [NVidia ]: HDA-Intel - HDA NVidia
HDA NVidia at 0xf3080000 irq 17
2 [amplifier ]: USB-Audio - 4.1 amplifier
4.1 amplifier at usb-0000:00:14.0-5, full speed
的输出aplay -l是：
**** List of PLAYBACK Hardware Devices ****
card 0: HDMI [HDA Intel HDMI], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: HDMI [HDA Intel HDMI], device 8: HDMI 2 [HDMI 2]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 7: HDMI 1 [HDMI 1]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 2: amplifier [4.1 amplifier], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0
的输出aplay -L为：
null
Discard all samples (playback) or generate zero samples (capture)
pulse
PulseAudio Sound Server
hdmi:CARD=HDMI,DEV=0
HDA Intel HDMI, HDMI 0
HDMI Audio Output
hdmi:CARD=HDMI,DEV=1
HDA Intel HDMI, HDMI 1
HDMI Audio Output
hdmi:CARD=HDMI,DEV=2
HDA Intel HDMI, HDMI 2
HDMI Audio Output
dmix:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Direct sample mixing device
dmix:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Direct sample mixing device
dmix:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Direct sample mixing device
dsnoop:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Direct sample snooping device
dsnoop:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Direct sample snooping device
dsnoop:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Direct sample snooping device
hw:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Direct hardware device without any conversions
hw:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Direct hardware device without any conversions
hw:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Direct hardware device without any conversions
plughw:CARD=HDMI,DEV=3
HDA Intel HDMI, HDMI 0
Hardware device with all software conversions
plughw:CARD=HDMI,DEV=7
HDA Intel HDMI, HDMI 1
Hardware device with all software conversions
plughw:CARD=HDMI,DEV=8
HDA Intel HDMI, HDMI 2
Hardware device with all software conversions
hdmi:CARD=NVidia,DEV=0
HDA NVidia, HDMI 0
HDMI Audio Output
hdmi:CARD=NVidia,DEV=1
HDA NVidia, HDMI 1
HDMI Audio Output
dmix:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample mixing device
dmix:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample mixing device
dsnoop:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct sample snooping device
dsnoop:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct sample snooping device
hw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Direct hardware device without any conversions
hw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Direct hardware device without any conversions
plughw:CARD=NVidia,DEV=3
HDA NVidia, HDMI 0
Hardware device with all software conversions
plughw:CARD=NVidia,DEV=7
HDA NVidia, HDMI 1
Hardware device with all software conversions
default:CARD=amplifier
4.1 amplifier, USB Audio
Default Audio Device
sysdefault:CARD=amplifier
4.1 amplifier, USB Audio
Default Audio Device
front:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Front speakers
surround21:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Direct sample mixing device
dsnoop:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Direct sample snooping device
hw:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Direct hardware device without any conversions
plughw:CARD=amplifier,DEV=0
4.1 amplifier, USB Audio
Hardware device with all software conversions
pulseaudio安装并运行系统后，我在“设备”中选择了4.1 Amplifier设备，可以在声音测试中听到声音。甚至可以正常工作。sound settingsOutputVLC Player
但是现在卸载后pulseaudio，我尝试在card 2 USB-Audio - 4.1 amplifier列出的设备上播放声音aplay -L，但音量太低，我几乎听不到任何声音。
我已确保音量已取消静音并将4.1 Amplifier声卡设置为 100%，alsamixer但音量仍然非常低。
不确定这里发生了什么？