register_sound_dsp(9) [suse man page]

REGISTER_SOUND_DSP(9)						   Sound Devices					     REGISTER_SOUND_DSP(9)

NAME

       register_sound_dsp - register a DSP device

SYNOPSIS

       int register_sound_dsp(const struct file_operations * fops, int dev);

ARGUMENTS

       fops
	   File operations for the driver

       dev
	   Unit number to allocate

DESCRIPTION

       Allocate a DSP device. Unit is the number of the DSP requested. Pass -1 to request the next free DSP unit. On success the allocated number
       is returned, on failure a negative error code is returned.

       This function allocates both the audio and dsp device entries together and will always allocate them as a matching pair - eg dsp3/audio3

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010						     REGISTER_SOUND_DSP(9)

7(16 December 2012)													       7(16 December 2012)

NAME

       dsp - Open Sound System audio devices

DESCRIPTION

       /dev/dsp  is  the  default audio device in the system. It's connected to the main speakers and the primary recording source (such as micro-
       phone). The system administrator can set /dev/dsp to be a symbolic link to the desired default device. The ossinfo utility can be  used	to
       list the available audio devices in the system.

       /dev/dsp_mmap,  /dev/dsp_ac3,  /dev/dsp_multich	and /dev/dsp_spdifout are default audio devices for specific applications such as games or
       media (DVD) players.

DIRECT ACCESS AUDIO DEVICE FILES

       OSS 4.0 (and later) will create audio devices under /dev/oss/<device> directory.  For example  /dev/oss/sblive0/pcm0  is  the  first  audio
       device  that belongs to the first Sound Blaster Live! or Audigy card in the system. These direct devices are used when an application needs
       to access specific audio device (instead of the default one).

       You can use the ossinfo(1) utility with the -a option to get a list of the available audio devices in the system.

LEGACY AUDIO DEVICE FILES

       Traditionally OSS has created device files like /dev/dsp0 to /dev/dspN for each audio device in the system. OSS	4.0  still  supports  this
       legacy  naming.	 These	files  are symbolic links to the actual device files located under /dev/oss. The ossdevlinks(8) utility is used to
       manage these links and it will be automatically invoked when OSS is started.

COMPATIBILITY

       o  The /dev/dsp (default() audio device file will be supported by all OSS implementations and versions.

       o  The special purpose audio default devices (such as /dev/dsp_mmap) are only supported by OSS 4.0 and later.

       o  The legacy audio device files (such as /dev/dsp1) are supported by all OSS versions and implementations.

       o  New style audio device files (under /dev/oss) are only supported by OSS 4.0 and later. However some independent OSS implementations  may
	  only support the legacy naming even they are otherwise OSS 4.0 compatible.

       o  /dev/dsp0 doesn't exist in all Linux systems which use /dev/dsp for the same purpose. In such systems /dev/dsp points to the first audio
	  device and /dev/dsp1 to the second.

PROGRAMMING INFORMATION

       See the Audio Programming section of the OSS Programmer's Guide (DSP(2)) for more info.

OPTIONS

       None

FILES

       o /dev/dsp
	      Default audio device

       o /dev/dsp_mmap
	      Default audio device for applications using mmap(2)

       o /dev/dsp_ac3
	      Default audio device for applications sending Dolby Digital (AC3) audio to an external receiver.

       o /dev/dsp_multich
	      Default multichannel (4.0-7.1) audio output device

       o /dev/dsp_spdifout
	      Default digital audio (S/PDIF) output device

       o /dev/oss/<driver>/pcmN
	      Direct access device files for individual audio devices.

       o /dev/dsp0 to /dev/dspN
	      Legacy style direct access audio device files.

AUTHOR

       4Front Technologies

OSS Devices														       7(16 December 2012)