ALSA

参考一
参考二
参考三

如何查看ALSA的版本：

$ cat /proc/asound/version
Advanced Linux Sound Architecture Driver Version k4.11.4-1.el7.centos.x86_64.

如何查看ALSA相关的驱动：

$ lsmod | grep snd
 snd_hda_codec_hdmi     49152  1
snd_hda_codec_realtek    90112  1
snd_hda_codec_generic    69632  1 snd_hda_codec_realtek
snd_hda_intel          40960  0
snd_hda_codec         126976  4 snd_hda_intel,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_codec_realtek
snd_hda_core           81920  5 snd_hda_intel,snd_hda_codec,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_hda_codec_realtek
snd_hwdep              16384  1 snd_hda_codec
snd_seq                65536  0
snd_seq_device         16384  1 snd_seq
snd_pcm                98304  4 snd_hda_intel,snd_hda_codec,snd_hda_core,snd_hda_codec_hdmi
snd_timer              32768  2 snd_seq,snd_pcm
snd                    77824  10 snd_hda_intel,snd_hwdep,snd_seq,snd_hda_codec,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_generic,snd_seq_device,snd_hda_codec_realtek,snd_pcm
soundcore              16384  1 snd

如何查看当前的声卡：

$ cat /proc/asound/cards
 0 [PCH            ]: HDA-Intel - HDA Intel PCH
                      HDA Intel PCH at 0xdf120000 irq 128

如何查看声卡里面的codec信息：

$ ls /proc/asound/card0/codec#*
/proc/asound/card0/codec#0  /proc/asound/card0/codec#2
$ cat /proc/asound/card0/codec#* | grep Codec
Codec: Realtek ALC662 rev3
Codec: Intel Skylake HDMI

如何查看PCM设备列表：

$ cat /proc/asound/pcm
00-00: ALC662 rev3 Analog : ALC662 rev3 Analog : playback 1 : capture 1
00-01: ALC662 rev3 Digital : ALC662 rev3 Digital : playback 1
00-03: HDMI 0 : HDMI 0 : playback 1
00-07: HDMI 1 : HDMI 1 : playback 1
00-08: HDMI 2 : HDMI 2 : playback 1
00-09: HDMI 3 : HDMI 3 : playback 1
00-10: HDMI 4 : HDMI 4 : playback 1

ALSA的文件系统接口：

/proc/asound
/dev/snd
/sys/class/sound