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Commit 597603d6 authored by Jaroslav Kysela's avatar Jaroslav Kysela
Browse files

ALSA: introduce the snd-aloop module for the PCM loopback 



The snd-aloop module allows redirecting of the PCM playback in the
kernel back to the user space using the standard ALSA PCM capture API.

The module also allows time synchronization with another timing source
and notifications of playback stream parameter changes.

Signed-off-by: default avatarJaroslav Kysela <perex@perex.cz>
parent 9fe6206f

sound/drivers/Kconfig

+19 −0
Original line number Original line Diff line number Diff line
@@ -74,6 +74,25 @@ config SND_DUMMY 
	  To compile this driver as a module, choose M here: the module

	  To compile this driver as a module, choose M here: the module

	  will be called snd-dummy.

	  will be called snd-dummy.





config SND_ALOOP

        tristate "Generic loopback driver (PCM)"

        select SND_PCM

        help

          Say 'Y' or 'M' to include support for the PCM loopback device.

	  This module returns played samples back to the user space using

	  the standard ALSA PCM device. The devices are routed 0->1 and

          1->0, where first number is the playback PCM device and second

	  number is the capture device. Module creates two PCM devices and

	  configured number of substreams (see the pcm_substreams module

          parameter).



	  The looback device allow time sychronization with an external

	  timing source using the time shift universal control (+-20%

	  of system time).



	  To compile this driver as a module, choose M here: the module

	  will be called snd-aloop.



config SND_VIRMIDI

config SND_VIRMIDI

	tristate "Virtual MIDI soundcard"

	tristate "Virtual MIDI soundcard"

	depends on SND_SEQUENCER

	depends on SND_SEQUENCER

sound/drivers/Makefile

+2 −0
Original line number Original line Diff line number Diff line
@@ -4,6 +4,7 @@ 
#

#





snd-dummy-objs := dummy.o

snd-dummy-objs := dummy.o

snd-aloop-objs := aloop.o

snd-mtpav-objs := mtpav.o

snd-mtpav-objs := mtpav.o

snd-mts64-objs := mts64.o

snd-mts64-objs := mts64.o

snd-portman2x4-objs := portman2x4.o

snd-portman2x4-objs := portman2x4.o
@@ -13,6 +14,7 @@ snd-ml403-ac97cr-objs := ml403-ac97cr.o pcm-indirect2.o 




# Toplevel Module Dependency

# Toplevel Module Dependency

obj-$(CONFIG_SND_DUMMY) += snd-dummy.o

obj-$(CONFIG_SND_DUMMY) += snd-dummy.o

obj-$(CONFIG_SND_ALOOP) += snd-aloop.o

obj-$(CONFIG_SND_VIRMIDI) += snd-virmidi.o

obj-$(CONFIG_SND_VIRMIDI) += snd-virmidi.o

obj-$(CONFIG_SND_SERIAL_U16550) += snd-serial-u16550.o

obj-$(CONFIG_SND_SERIAL_U16550) += snd-serial-u16550.o

obj-$(CONFIG_SND_MTPAV) += snd-mtpav.o

obj-$(CONFIG_SND_MTPAV) += snd-mtpav.o

sound/drivers/aloop.c

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