TURN YOUR LINUX COMPUTER INTO A HUGE ANDROID USB ACCESSORY

参考文章：

关于USB-AUDIO使用ALSA编程的一点问题:http://blog.chinaunix.net/uid-25272011-id-3153434.html

 
手把手教你用树莓派(Raspberry Pi)打造宇宙翻译机 :
http://oszine.com/universal-translator/
Creating a Simple USB Audio and HID Accesory for Android using a Raspberry Pi:
http://tcorley.me/simple-aoa-raspberry-pi/
https://bugzilla.kernel.org/show_bug.cgi?id=60769
https://source.android.com/devices/accessories/aoa2.html#hid-support
https://source.android.com/devices/input/overview.html

http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux
https://wiki.archlinux.org/index.php/Advanced_Linux_Sound_Architecture#Configuration
http://wiki.audacityteam.org/wiki/USB_mic_on_Linux
https://help.ubuntu.com/community/UbuntuStudio/UsbAudioDevices

http://www.alsa-project.org/main/index.php/Matrix:Module-usb-audio
http://raspberrypi.stackexchange.com/questions/40831/how-do-i-configure-my-sound-for-jasper-on-raspbian-jessie

http://android.serverbox.ch/?p=262

http://forum.xda-developers.com/showthread.php?t=1852343

https://github.com/KunYi/pcaoa/blob/master/sw_droid_accessory_mode.cpp

http://oszine.com/universal-translator/
http://wiki.audacityteam.org/index.php?title=USB_mic_on_Linux

http://users.suse.com/~mana/alsa090_howto.html

http://equalarea.com/paul/alsa-audio.html

Linux-ALSA声卡驱动

Linux_ALSA声卡驱动原理分析
参考代码：
sw_droid_accessory_mode

root@clq-ubuntu:~# sudo apt-get install mtpfs libfuse-dev libmad0-dev

apt-get source libusb

apt-get install libusb-dev

apt-get install libusb-1.0-0-dev

gcc simplectrl.c -I/usr/include/ -o simplectrl -lusb-1.0 -I/usr/include/ -I/usr/include/libusb-1.0

如何判断是否支持Audio：
sudo lsusb -d 18d1:2d04 -v | grep "Audio"

      bInterfaceClass         1 Audio # 表示支持Audio

      AudioControl Interface Descriptor:

      AudioControl Interface Descriptor:

      AudioControl Interface Descriptor:

      AudioControl Interface Descriptor:

      bInterfaceClass         1 Audio

      bInterfaceClass         1 Audio

      AudioStreaming Interface Descriptor:

      AudioStreaming Interface Descriptor:

        AudioControl Endpoint Descriptor:
cat /proc/asound/cards

 0 [AudioPCI       ]: ENS1371 - Ensoniq AudioPCI

                      Ensoniq AudioPCI ENS1371 at 0x2080, irq 16

 1 [Pro            ]: USB-Audio - MX4 Pro

                      MEIZU MX4 Pro at usb-0000:02:03.0-1, high speed

cat /proc/asound/modules

 0 snd_ens1371

 1 snd_usb_audio

card 0（预设输出）的驱动程序是snd_ens1371，。card 1的驱动程序是snd_usb_audio
调试ALSA常用命令：
aplay -l

ls -lart /dev/snd

cat /dev/sndstat

lsmod | grep snd

alsactl -v //查看ALSA版本

lsusb -vvv

wget -O alsa-info.sh http://www.alsa-project.org/alsa-info.sh && chmod +x ./alsa-info.sh && ./alsa-info.sh
┌───────────────────────────── AlsaMixer v1.0.22 ──────────────────────────────┐

│ Card: MX4 Pro                                        F1:  Help               │

│ Chip: USB Mixer                                      F2:  System information │

│ View: F3: Playback  F4: Capture  F5: All             F6:  Select sound card  │

│ Item:                                                Esc: Exit               │

│                                                                              │

│                                                                              │

│                                                                              │

│                This sound device does not have any controls.  

安装alsa-driver,alsa-utils,alsa-lib

参考：http://www.360doc.com/content/12/0913/22/9615799_235991212.shtml

http://www.alsa-project.org/main/index.php/Download
//查看当前版本号

cat /proc/asound/version

Advanced Linux Sound Architecture Driver Version 1.0.21.

//停止ALSA应用

sudo /sbin/alsa-utils stop
//安装编译所依赖的工具

sudo apt-get -y install build-essential ncurses-dev gettext xmlto libasound2-dev

sudo apt-get -y install linux-headers-`uname -r` libncursesw5-dev
//下载源文件

cd ~

rm -rf ~/alsa* ~/.pulse*

wget ftp://ftp.alsa-project.org/pub/driver/alsa-driver-1.0.23.tar.bz2

wget ftp://ftp.alsa-project.org/pub/lib/alsa-lib-1.0.23.tar.bz2

wget ftp://ftp.alsa-project.org/pub/utils/alsa-utils-1.0.23.tar.bz2
//删除原来的目录，并拷贝源文件过来

sudo rm -rf /usr/src/alsa

sudo mkdir -p /usr/src/alsa

cd /usr/src/alsa

sudo cp ~/alsa* .
//解压

sudo tar xjf alsa-driver*

sudo tar xjf alsa-lib*

sudo tar xjf alsa-utils*
//编译driver

cd alsa-driver*

sudo ./configure

sudo make

sudo make install
//编译library

cd ../alsa-lib*

sudo ./configure

sudo make

sudo make install
//编译应用

cd ../alsa-utils*

sudo ./configure

sudo make

sudo make install
//删除源文件

rm -f ~/alsa-driver*

rm -f ~/alsa-lib*

rm -f ~/alsa-utils*

//重启系统

sudo reboot

//查看版本号

cat /proc/asound/version

Advanced Linux Sound Architecture Driver Version 1.0.23.

Compiled on May 2 2010 for kernel 2.6.32-21-generic (SMP).
但是用下面的命令却没有生效   不知道为什么。
denny@ubuntu:/dev/snddpkg -l | grep asou

ii  libasound2                           1.0.22-0ubuntu7                                 shared library for ALSA applications

ii  libasound2-dev                       1.0.22-0ubuntu7                                 shared library for ALSA applications -- deve

ii  libasound2-plugins                   1.0.22-0ubuntu6                                 ALSA library additional plugins

denny@ubuntu:/dev/snd dpkg -l | grep alsa

ii  alsa-base                            1.0.22.1+dfsg-0ubuntu3                          ALSA driver configuration files

ii  alsa-firmware-loaders                1.0.22-0ubuntu1                                 ALSA software loaders for specific hardware

ii  alsa-source                          1.0.22.1+dfsg-0ubuntu3                          ALSA driver sources

ii  alsa-utils                           1.0.22-0ubuntu5                                 ALSA utilities

ii  alsamixergui                         0.9.0rc2-1-9                                    graphical soundcard mixer for ALSA soundcard

ii  bluez-alsa                           4.60-0ubuntu8                                   Bluetooth audio support

ii  gstreamer0.10-alsa                   0.10.28-1                                       GStreamer plugin for ALSA

//确认功能是否正常

sudo alsaconf
When I use Ubuntu 10.04, after switch LG G4 to Audio mode:
ls /dev/snd

by-id    controlC0  midiC0D0  pcmC0D0p    timer

by-path  controlC1  pcmC0D0c  pcmC0D1p  seq

 sudo arecord -l

[sudo] password for denny:

**** List of CAPTURE Hardware Devices ****

card 0: AudioPCI [Ensoniq AudioPCI], device 0: ES1371/1 [ES1371 DAC2/ADC]

  Subdevices: 1/1

  Subdevice #0: subdevice #0

I can not find my USB Audio device,only controlC1 is shown but no pcmC1D0c.
So I have to update my Ubuntu from 10.04 to 12.04 ,then my USB Audio device appear:
ls /dev/snd

by-id    controlC0  midiC0D0  pcmC0D0p  pcmC1D0c  timer

by-path  controlC1  pcmC0D0c  pcmC0D1p  seq

 sudo arecord -l

[sudo] password for denny:

**** List of CAPTURE Hardware Devices ****

card 0: AudioPCI [Ensoniq AudioPCI], device 0: ES1371/1 [ES1371 DAC2/ADC]

  Subdevices: 1/1

  Subdevice #0: subdevice #0

card 1: Phone [LGE Android Phone], device 0: USB Audio [USB Audio]

  Subdevices: 1/1

  Subdevice #0: subdevice #0

But I have another issue:
 
http://comments.gmane.org/gmane.linux.usb.general/71286
sudo arecord  -f cd -d 5  -D hw:1,0

Recording WAVE 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

arecord: pcm_read:1801: read error: Input/output error

#dmesg

[ 5092.841145] capture write error (DMA or IRQ trouble?)

[ 5093.840767] timeout: still 11 active urbs on EP #82

[ 5094.840698] timeout: still 10 active urbs on EP #82

[ 5095.840688] timeout: still 9 active urbs on EP #82