alsa-configuration.txt

优龙2410linux2.6.8内核源代码

			* PINE Schubert 32 PCI

    reverb    - Reverb Enable - 1 = enable, 0 = disable (default)
                  - SoundCard must have onboard SRAM for this.
    mge       - Mic Gain Enable - 1 = enable, 0 = disable (default)
    
    Module supports up to 8 cards and autoprobe.

  Module snd-serial-u16550
  ------------------------

    Module for UART16550A serial MIDI ports.

    port	- port # for UART16550A chip
    irq		- IRQ # for UART16550A chip, -1 = poll mode
    speed	- speed in bauds (9600,19200,38400,57600,115200)
		  38400 = default
    base	- base for divisor in bauds (57600,115200,230400,460800)
		  115200 = default
    outs	- number of MIDI ports in a serial port (1-4)
		  1 = default
    adaptor	- Type of adaptor.
                  0 = Soundcanvas, 1 = MS-124T, 2 = MS-124W S/A,
		  3 = MS-124W M/B, 4 = Generic
    
    Module supports up to 8 cards. This module does not support autoprobe
    thus the main port must be specified!!! Other options are optional.

  Module snd-trident
  ------------------

    Module for Trident 4DWave DX/NX soundcards.
			* Best Union  Miss Melody 4DWave PCI
			* HIS  4DWave PCI
			* Warpspeed  ONSpeed 4DWave PCI
			* AzTech  PCI 64-Q3D
			* Addonics  SV 750
			* CHIC  True Sound 4Dwave
			* Shark  Predator4D-PCI
			* Jaton  SonicWave 4D

    pcm_channels   - max channels (voices) reserved for PCM
    wavetable_size - max wavetable size in kB (4-?kb)

    Module supports up to 8 cards and autoprobe.

    The power-management is supported.

  Module snd-usb-audio
  --------------------

    Module for USB audio and USB MIDI devices.

    vid             - Vendor ID for the device (optional)
    pid             - Product ID for the device (optional)

    This module supports up to 8 cards, autoprobe and hotplugging.

  Module snd-via82xx
  ------------------

    Module for AC'97 motherboards based on VIA 82C686A/686B, 8233,
    8233A, 8233C, 8235 (south) bridge.

    mpu_port	- 0x300,0x310,0x320,0x330, otherwise obtain BIOS setup
		  [VIA686A/686B only]
    joystick	- Enable joystick (default off) [VIA686A/686B only]
    ac97_clock	- AC'97 codec clock base (default 48000Hz)
    dxs_support	- support DXS channels,
		  0 = auto (defalut), 1 = enable, 2 = disable,
		  3 = 48k only, 4 = no VRA
		  [VIA8233/C,8235 only]
    ac97_quirk  - AC'97 workaround for strange hardware
                  See the description of intel8x0 module for details.

    Module supports autoprobe and multiple bus-master chips (max 8).

    Note: on some SMP motherboards like MSI 694D the interrupts might
          not be generated properly.  In such a case, please try to
          set the SMP (or MPS) version on BIOS to 1.1 instead of
          default value 1.4.  Then the interrupt number will be
          assigned under 15. You might also upgrade your BIOS.
    
    Note: VIA8233/5 (not VIA8233A) can support DXS (direct sound)
	  channels as the first PCM.  On these channels, up to 4
	  streams can be played at the same time.
	  As default (dxs_support = 0), 48k fixed rate is chosen
	  except for the known devices since the output is often
	  noisy except for 48k on some mother boards due to the
	  bug of BIOS.
	  Please try once dxs_support=1 and if it works on other
	  sample rates (e.g. 44.1kHz of mp3 playback), please let us
	  know the PCI subsystem vendor/device id's (output of
	  "lspci -nv").
	  If it doesn't work, try dxs_support=4.  If it still doesn't
	  work and the default setting is ok, dxs_support=3 is the
	  right choice.  If the default setting doesn't work at all,
	  try dxs_support=2 to disable the DXS channels.
	  In any cases, please let us know the result and the
	  subsystem vendor/device ids.

    Note: for the MPU401 on VIA823x, use snd-mpu401 driver
	  additonally.  The mpu_port option is for VIA686 chips only.

  Module snd-virmidi
  ------------------

    Module for virtual rawmidi devices.
    This module creates virtual rawmidi devices which communicate
    to the corresponding ALSA sequencer ports.

    midi_devs	- MIDI devices # (1-8, default=4)
    
    Module supports up to 8 cards.

  Module snd-vx222
  ----------------

    Module for Digigram VX-Pocket VX222, V222 v2 and Mic cards.

    mic		- Enable Microphone on V222 Mic (NYI)
    ibl		- Capture IBL size. (default = 0, minimum size)

    Module supports up to 8 cards.

    For loading the firmware, use vxloader utility in alsa-tools
    and alsa-firmware packages.  You can load the firmware automatically
    by adding the following to /etc/modprobe.conf

	install snd-vx222 /sbin/modprobe --first-time -i snd-vx222 && /usr/bin/vxloader

    (for 2.2/2.4 kernels, add "post-install /usr/bin/vxloader" to
     /etc/modules.conf, instead.)
    IBL size defines the interrupts period for PCM.  The smaller size
    gives smaller latency but leads to more CPU consumption, too.
    The size is usually aligned to 126.  As default (=0), the smallest
    size is chosen.  The possible IBL values can be found in
    /proc/asound/cardX/vx-status proc file.

  Module snd-vxpocket
  -------------------

    Module for Digigram VX-Pocket VX2 PCMCIA card.

    irq_mask - IRQ bitmask, specifies the available IRQs as bits
               (default = 0xffff, all available)
    irq_list - List of available interrupts (default = -1, not specified)
               4 numbers must be given (if specified).
    ibl      - Capture IBL size. (default = 0, minimum size)

    Module supports up to 8 cards.  The module is compiled only when
    PCMCIA is supported on kernel.

    To activate the driver via the card manager, you'll need to set
    up /etc/pcmcia/vxpocket.conf.  See the sound/pcmcia/vx/vxpocket.c.

    For loading the firmware, use vxloader utility in alsa-tools
    and alsa-firmware packages.

    The irq_mask and irq_list are provided to avoid allocation of
    specific IRQs.  Usually you don't need to specify them.

    About capture IBL, see the description of snd-vx222 module.

    Note: the driver is build only when CONFIG_ISA is set.
    
  Module snd-vxp440
  -----------------

    Module for Digigram VX-Pocket 440 PCMCIA card.

    irq_mask - IRQ bitmask, specifies the available IRQs as bits
    irq_list - List of available interrupts (default = -1, not specified)
               4 numbers must be given (if specified).
    ibl      - Capture IBL size. (default = 0, minimum size)

    Module supports up to 8 cards.  The module is compiled only when
    PCMCIA is supported on kernel.

    To activate the driver via the card manager, you'll need to set
    up /etc/pcmcia/vxp440.conf.  See the sound/pcmcia/vx/vxp440.c.

    For loading the firmware, use vxloader utility in alsa-tools
    and alsa-firmware packages.

    The irq_mask and irq_list are provided to avoid allocation of
    specific IRQs.  Usually you don't need to specify them.

    About capture IBL, see the description of snd-vx222 module.

    Note: the driver is build only when CONFIG_ISA is set.
    
  Module snd-ymfpci
  -----------------

    Module for Yamaha PCI chips (YMF72x, YMF74x & YMF75x).

    mpu_port      - 0x300,0x330,0x332,0x334, 0 (disable) by default,
                    1 (auto-detect for YMF744/754 only)
    fm_port       - 0x388,0x398,0x3a0,0x3a8, 0 (disable) by default
                    1 (auto-detect for YMF744/754 only)
    joystick_port - 0x201,0x202,0x204,0x205, 0 (disable) by default,
                    1 (auto-detect)
    rear_switch   - enable shared rear/line-in switch (bool)

    Module supports autoprobe and multiple chips (max 8).

    The power-management is supported.

  Module snd-pdaudiocf
  --------------------

    Module for Sound Core PDAudioCF soundcard.

    irq_mask	  - IRQ mask (PCMCIA type)
    irq_list	  - List of available interrupts for this soundcard

    Note: the driver is build only when CONFIG_ISA is set.


Configuring Non-ISAPNP Cards
============================

When the kernel is configured with ISA-PnP support, the modules
supporting the isapnp cards will have module options "isapnp".
If this option is set, *only* the ISA-PnP devices will be probed.
For probing the non ISA-PnP cards, you have to pass "isapnp=0" option
together with the proper i/o and irq configuration.

When the kernel is configured without ISA-PnP support, isapnp option
will be not built in.


Module Autoloading Support
==========================

The ALSA drivers can be loaded automatically on demand by defining
module aliases.  The string 'snd-card-%1' is requested for ALSA native
devices where %i is soundcard number from zero to seven.

To auto-load an ALSA driver for OSS services, define the string
'sound-slot-%i' where %i means the slot number for OSS, which
corresponds to the card index of ALSA.  Usually, define this
as the the same card module.

An example configuration for a single emu10k1 card is like below:
----- /etc/modprobe.conf
alias snd-card-0 snd-emu10k1
alias sound-slot-0 snd-emu10k1
----- /etc/modprobe.conf

The available number of auto-loaded soundcards depends on the module
option "cards_limit" of snd module.  As default it's set to 1.
To enable the auto-loading of multiple cards, specify the number of
soundcards in that option.

When multiple cards are available, it'd better to specify the index
number for each card via module option, too, so that the order of
cards is kept consistent.

An example configuration for two soundcards is like below:

----- /etc/modprobe.conf
# ALSA portion
options snd cards_limit=2
alias snd-card-0 snd-interwave
alias snd-card-1 snd-ens1371
options snd-interwave index=0
options snd-ens1371 index=1
# OSS/Free portion
alias sound-slot-0 snd-interwave
alias sound-slot-1 snd-ens1371
----- /etc/moprobe.conf

In this example, the interwave card is always loaded as the first card
(index 0) and ens1371 as the second (index 1).


ALSA PCM devices to OSS devices mapping
=======================================

/dev/snd/pcmC0D0  -> /dev/audio0 (/dev/audio) -> minor 4
/dev/snd/pcmC0D0  -> /dev/dsp0 (/dev/dsp)     -> minor 3
/dev/snd/pcmC0D1  -> /dev/adsp0 (/dev/adsp)   -> minor 12
/dev/snd/pcmC1D0  -> /dev/audio1              -> minor 4+16 = 20
/dev/snd/pcmC1D0  -> /dev/dsp1                -> minor 3+16 = 19
/dev/snd/pcmC1D1  -> /dev/adsp1               -> minor 12+16 = 28
/dev/snd/pcmC2D0  -> /dev/audio2              -> minor 4+32 = 36
/dev/snd/pcmC2D0  -> /dev/dsp2                -> minor 3+32 = 39
/dev/snd/pcmC2D1  -> /dev/adsp2               -> minor 12+32 = 44

The first number from /dev/snd/pcmC{X}D{Y} expression means soundcard number
and second means device number.
Please note that the device mapping above may be varied via the module
options of snd-pcm-oss module.


DEVFS support
=============

The ALSA driver fully supports the devfs extension.
You should add lines below to your devfsd.conf file:

LOOKUP snd MODLOAD ACTION snd
REGISTER ^sound/.* PERMISSIONS root.audio 660
REGISTER ^snd/.* PERMISSIONS root.audio 660

Warning: These lines assume that you have the audio group in your system.
         Otherwise replace audio word with another group name (root for
         example).


Proc interfaces (/proc/asound)
==============================

/proc/asound/card#/pcm#[cp]/oss
-------------------------------
  String "erase" - erase all additional informations about OSS applications
  String "<app_name> <fragments> <fragment_size> [<options>]"

   <app_name> - name of application with (higher priority) or without path
   <fragments> - number of fragments or zero if auto
   <fragment_size> - size of fragment in bytes or zero if auto
   <options> - optional parameters
	  - disable   the application tries to open a pcm device for
		      this channel but does not want to use it.
		      (Cause a bug or mmap needs)
		      It's good for Quake etc...
	  - direct    don't use plugins
	  - block     force block mode (rvplayer)
	  - non-block force non-block mode
	  - whole-frag  write only whole fragments (optimization affecting
			playback only)
	  - no-silence  do not fill silence ahead to avoid clicks

  Example: echo "x11amp 128 16384" > /proc/asound/card0/pcm0p/oss
           echo "squake 0 0 disable" > /proc/asound/card0/pcm0c/oss
	   echo "rvplayer 0 0 block" > /proc/asound/card0/pcm0p/oss


Links
=====

  ALSA project homepage
       http://www.alsa-project.org