snd_card_register(9) [centos man page]

SND_CARD_REGISTER(9)					  Management of Cards and Device				      SND_CARD_REGISTER(9)

NAME

       snd_card_register - register the soundcard

SYNOPSIS

       int snd_card_register(struct snd_card * card);

ARGUMENTS

       card
	   soundcard structure

DESCRIPTION

       This function registers all the devices assigned to the soundcard. Until calling this, the ALSA control interface is blocked from the
       external accesses. Thus, you should call this function at the end of the initialization of the card.

RETURN

       Zero otherwise a negative error code if the registration failed.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						      SND_CARD_REGISTER(9)

AMIXER(1)						      General Commands Manual							 AMIXER(1)

NAME

       amixer - command-line mixer for ALSA soundcard driver

SYNOPSIS

       amixer [-option] [cmd]

DESCRIPTION

       amixer allows command-line control of the mixer for the ALSA soundcard driver.  amixer supports multiple soundcards.

       amixer  with no arguments will display the current mixer settings for the default soundcard and device. This is a good way to see a list of
       the simple mixer controls you can use.

COMMANDS

       help   Shows syntax.

       info   Shows the information about a mixer device.

       scontrols
	      Shows a complete list of simple mixer controls.

       scontents
	      Shows a complete list of simple mixer controls with their contents.

       set or sset <SCONTROL> <PARAMETER> ...
	      Sets the simple mixer control contents. The parameter can be the volume either as a percentage from 0% to 100% with % suffix,  a	dB
	      gain  with dB suffix (like -12.5dB), or an exact hardware value.	The dB gain can be used only for the mixer elements with available
	      dB information.  When plus(+) or minus(-) letter is appended after volume value, the volume is incremented or decremented  from  the
	      current value, respectively.

	      The parameters cap, nocap, mute, unmute, toggle are used to change capture (recording) and muting for the group specified.

	      The  optional modifiers can be put as extra parameters to specify the stream direction or channels to apply.  The modifiers playback
	      and capture specify the stream, and the modifiers front, rear, center, woofer are used to specify channels to be changed.

	      A simple mixer control must be specified. Only one device can be controlled at a time.

       get or sget <SCONTROL>
	      Shows the simple mixer control contents.

	      A simple mixer control must be specified. Only one device can be controlled at a time.

       controls
	      Shows a complete list of card controls.

       contents
	      Shows a complete list of card controls with their contents.

       cset <CONTROL> <PARAMETER> ...
	      Sets the card control contents. The identifier has these components: iface, name, index, device, subdevice, numid. The next argument
	      specifies the value of control.

       cget <CONTROL>
	      Shows the card control contents. The identifier has same syntax as for the cset command.

OPTIONS

       -c card

	      Select the card number to control. The device name created from this parameter has syntax 'hw:N' where N is specified card number.

       -D device

	      Select the device name to control. The default control name is 'default'.

       -s | --stdin

	      Read from stdin and execute the command on each line sequentially.  When this option is given, the command in command-line arguments
	      is ignored.

	      Only sset and cset are accepted.	Other commands are ignored.  The commands to unmatched ids are ignored without errors too.

       -h     Help: show syntax.

       -q     Quiet mode. Do not show results of changes.

       -R     Use the raw value for evaluating the percentage representation.  This is the default mode.

       -M     Use the mapped volume for evaluating the percentage representation like alsamixer, to be more natural for human ear.

EXAMPLES

       amixer -c 1 sset Line,0 80%,40% unmute cap
	      will set the second soundcard's left line input volume to 80% and right line input to 40%, unmute it, and select it as a source  for
	      capture (recording).

       amixer -c 1 -- sset Master playback -20dB
	      will  set  the  master  volume  of  the second card to -20dB.  If the master has multiple channels, all channels are set to the same
	      value.

       amixer -c 1 set PCM 2dB+
	      will increase the PCM volume of the second card with 2dB.  When both playback and capture volumes exist, this  is  applied  to  both
	      volumes.

       amixer -c 2 cset iface=MIXER,name='Line Playback Volume",index=1 40%
	      will set the third soundcard's second line playback volume(s) to 40%

       amixer -c 2 cset numid=34 40%
	      will set the 34th soundcard element to 40%

SEE ALSO

	alsamixer(1)

BUGS

       None known.

AUTHOR

       amixer is by Jaroslav Kysela <perex@perex.cz>.  This document is by Paul Winkler <zarmzarm@erols.com> and Jaroslav Kysela <perex@perex.cz>.

								    11 Aug 2000 							 AMIXER(1)