alsa-configuration.txt

底层驱动开发

		Advanced Linux Sound Architecture - Driver
		==========================================
			    Configuration guide


Kernel Configuration
====================

To enable ALSA support you need at least to build the kernel with
primary sound card support (CONFIG_SOUND).  Since ALSA can emulate OSS,
you don't have to choose any of the OSS modules.

Enable "OSS API emulation" (CONFIG_SND_OSSEMUL) and both OSS mixer and
PCM supports if you want to run OSS applications with ALSA.

If you want to support the WaveTable functionality on cards such as
SB Live! then you need to enable "Sequencer support"
(CONFIG_SND_SEQUENCER).

To make ALSA debug messages more verbose, enable the "Verbose printk"
and "Debug" options.  To check for memory leaks, turn on "Debug memory"
too.  "Debug detection" will add checks for the detection of cards.

Please note that all the ALSA ISA drivers support the Linux isapnp API
(if the card supports ISA PnP).  You don't need to configure the cards
using isapnptools.


Creating ALSA devices
=====================

This depends on your distribution, but normally you use the /dev/MAKEDEV
script to create the necessary device nodes.  On some systems you use a
script named 'snddevices'.


Module parameters
=================

The user can load modules with options. If the module supports more than
one card and you have more than one card of the same type then you can
specify multiple values for the option separated by commas.

Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.

  Module snd
  ----------

    The core ALSA module.  It is used by all ALSA card drivers.
    It takes the following options which have global effects.

    major	- major number for sound driver
		- Default: 116
    cards_limit
		- limiting card index for auto-loading (1-8)
		- Default: 1
		- For auto-loading more than one card, specify this
		  option together with snd-card-X aliases.
    device_mode
		- permission mask for dynamic sound device filesystem
		- This is available only when DEVFS is enabled
		- Default: 0666
		- E.g.: device_mode=0660

  
  Module snd-pcm-oss
  ------------------

    The PCM OSS emulation module.
    This module takes options which change the mapping of devices.

    dsp_map	- PCM device number maps assigned to the 1st OSS device.
		- Default: 0
    adsp_map	- PCM device number maps assigned to the 2st OSS device.
		- Default: 1
    nonblock_open
		- Don't block opening busy PCM devices.  Default: 1

    For example, when dsp_map=2, /dev/dsp will be mapped to PCM #2 of
    the card #0.  Similarly, when adsp_map=0, /dev/adsp will be mapped
    to PCM #0 of the card #0.
    For changing the second or later card, specify the option with
    commas, such like "dsp_map=0,1".

    nonblock_open option is used to change the behavior of the PCM
    regarding opening the device.  When this option is non-zero,
    opening a busy OSS PCM device won't be blocked but return
    immediately with EAGAIN (just like O_NONBLOCK flag).
    
  Module snd-rawmidi
  ------------------

    This module takes options which change the mapping of devices.
    similar to those of the snd-pcm-oss module.

    midi_map	- MIDI device number maps assigned to the 1st OSS device.
		- Default: 0
    amidi_map	- MIDI device number maps assigned to the 2st OSS device.
		- Default: 1

  Common parameters for top sound card modules
  --------------------------------------------

    Each of top level sound card module takes the following options.

    index	- index (slot #) of sound card
		- Values: 0 through 7 or negative
		- If nonnegative, assign that index number
                - if negative, interpret as a bitmask of permissible
		  indices; the first free permitted index is assigned
		- Default: -1
    id		- card ID (identifier or name)
		- Can be up to 15 characters long
		- Default: the card type
		- A directory by this name is created under /proc/asound/
		  containing information about the card
		- This ID can be used instead of the index number in
		  identifying the card
    enable  	- enable card
		- Default: enabled, for PCI and ISA PnP cards

  Module snd-ad1816a
  ------------------

    Module for sound cards based on Analog Devices AD1816A/AD1815 ISA chips.

    port	- port # for AD1816A chip (PnP setup)
    mpu_port	- port # for MPU-401 UART (PnP setup)
    fm_port	- port # for OPL3 (PnP setup)
    irq		- IRQ # for AD1816A chip (PnP setup)
    mpu_irq	- IRQ # for MPU-401 UART (PnP setup)
    dma1	- first DMA # for AD1816A chip (PnP setup)
    dma2	- second DMA # for AD1816A chip (PnP setup)
    clockfreq   - Clock frequency for AD1816A chip (default = 0, 33000Hz)
    
    Module supports up to 8 cards, autoprobe and PnP.
    
  Module snd-ad1848
  -----------------

    Module for sound cards based on AD1848/AD1847/CS4248 ISA chips.

    port	- port # for AD1848 chip
    irq		- IRQ # for AD1848  chip
    dma1	- DMA # for AD1848 chip (0,1,3)
    
    Module supports up to 8 cards. This module does not support autoprobe
    thus main port must be specified!!! Other ports are optional.
    
  Module snd-ad1889
  -----------------

    Module for Analog Devices AD1889 chips.

    ac97_quirk  - AC'97 workaround for strange hardware
                  See the description of intel8x0 module for details.

    This module supports up to 8 cards.

  Module snd-ali5451
  ------------------

    Module for ALi M5451 PCI chip.

    pcm_channels    - Number of hardware channels assigned for PCM
    spdif           - Support SPDIF I/O
    		    - Default: disabled

    Module supports autoprobe and multiple chips (max 8).

    The power-management is supported.

  Module snd-als100
  -----------------

    Module for sound cards based on Avance Logic ALS100/ALS120 ISA chips.

    port	- port # for ALS100 (SB16) chip (PnP setup)
    irq		- IRQ # for ALS100 (SB16) chip (PnP setup)
    dma8	- 8-bit DMA # for ALS100 (SB16) chip (PnP setup)
    dma16	- 16-bit DMA # for ALS100 (SB16) chip (PnP setup)
    mpu_port	- port # for MPU-401 UART (PnP setup)
    mpu_irq	- IRQ # for MPU-401 (PnP setup)
    fm_port	- port # for OPL3 FM (PnP setup)
    
    Module supports up to 8 cards, autoprobe and PnP.

  Module snd-als4000
  ------------------

    Module for sound cards based on Avance Logic ALS4000 PCI chip.

    joystick_port - port # for legacy joystick support.
                    0 = disabled (default), 1 = auto-detect
    
    Module supports up to 8 cards, autoprobe and PnP.

  Module snd-atiixp
  -----------------

    Module for ATI IXP 150/200/250/400 AC97 controllers.

    ac97_clock		- AC'97 clock (default = 48000)
    ac97_quirk		- AC'97 workaround for strange hardware
			  See "AC97 Quirk Option" section below.
    spdif_aclink	- S/PDIF transfer over AC-link (default = 1)

    This module supports up to 8 cards and autoprobe.

    ATI IXP has two different methods to control SPDIF output.  One is
    over AC-link and another is over the "direct" SPDIF output.  The
    implementation depends on the motherboard, and you'll need to
    choose the correct one via spdif_aclink module option.

  Module snd-atiixp-modem
  -----------------------

    Module for ATI IXP 150/200/250 AC97 modem controllers.

    Module supports up to 8 cards.

    Note: The default index value of this module is -2, i.e. the first
          slot is excluded.

  Module snd-au8810, snd-au8820, snd-au8830
  -----------------------------------------

    Module for Aureal Vortex, Vortex2 and Advantage device.

    pcifix	- Control PCI workarounds
		  0 = Disable all workarounds
		  1 = Force the PCI latency of the Aureal card to 0xff
		  2 = Force the Extend PCI#2 Internal Master for Efficient
		      Handling of Dummy Requests on the VIA KT133 AGP Bridge
		  3 = Force both settings
		  255 = Autodetect what is required (default)

    This module supports all ADB PCM channels, ac97 mixer, SPDIF, hardware
    EQ, mpu401, gameport. A3D and wavetable support are still in development.
    Development and reverse engineering work is being coordinated at
    http://savannah.nongnu.org/projects/openvortex/
    SPDIF output has a copy of the AC97 codec output, unless you use the
    "spdif" pcm device, which allows raw data passthru.
    The hardware EQ hardware and SPDIF is only present in the Vortex2 and 
    Advantage.

    Note: Some ALSA mixer applications don't handle the SPDIF sample rate 
           control correctly. If you have problems regarding this, try
           another ALSA compliant mixer (alsamixer works).

  Module snd-azt2320
  ------------------

    Module for sound cards based on Aztech System AZT2320 ISA chip (PnP only).

    port	- port # for AZT2320 chip (PnP setup)
    wss_port	- port # for WSS (PnP setup)
    mpu_port	- port # for MPU-401 UART (PnP setup)
    fm_port	- FM port # for AZT2320 chip (PnP setup)
    irq		- IRQ # for AZT2320 (WSS) chip (PnP setup)
    mpu_irq	- IRQ # for MPU-401 UART (PnP setup)
    dma1	- 1st DMA # for AZT2320 (WSS) chip (PnP setup)
    dma2	- 2nd DMA # for AZT2320 (WSS) chip (PnP setup)
    
    Module supports up to 8 cards, PnP and autoprobe.
    
  Module snd-azt3328
  ------------------

    Module for sound cards based on Aztech AZF3328 PCI chip.

    joystick	- Enable joystick (default off)

    Module supports up to 8 cards.

  Module snd-bt87x
  ----------------

    Module for video cards based on Bt87x chips.

    digital_rate - Override the default digital rate (Hz)
    load_all	- Load the driver even if the card model isn't known

    Module supports up to 8 cards.

    Note: The default index value of this module is -2, i.e. the first
          slot is excluded.

  Module snd-ca0106
  -----------------

    Module for Creative Audigy LS and SB Live 24bit

    Module supports up to 8 cards.


  Module snd-cmi8330
  ------------------

    Module for sound cards based on C-Media CMI8330 ISA chips.

    wssport	- port # for CMI8330 chip (WSS)
    wssirq	- IRQ # for CMI8330 chip (WSS)
    wssdma	- first DMA # for CMI8330 chip (WSS)
    sbport	- port # for CMI8330 chip (SB16)
    sbirq	- IRQ # for CMI8330 chip (SB16)
    sbdma8	- 8bit DMA # for CMI8330 chip (SB16)
    sbdma16	- 16bit DMA # for CMI8330 chip (SB16)

    Module supports up to 8 cards and autoprobe.

  Module snd-cmipci
  -----------------

    Module for C-Media CMI8338 and 8738 PCI sound cards.

    mpu_port	- 0x300,0x310,0x320,0x330, 0 = disable (default)
    fm_port     - 0x388 (default), 0 = disable (default)
    soft_ac3    - Software-conversion of raw SPDIF packets (model 033 only)
                  (default = 1)
    joystick_port - Joystick port address (0 = disable, 1 = auto-detect)

    Module supports autoprobe and multiple chips (max 8).
    
  Module snd-cs4231
  -----------------

    Module for sound cards based on CS4231 ISA chips.

    port	- port # for CS4231 chip
    mpu_port	- port # for MPU-401 UART (optional), -1 = disable
    irq		- IRQ # for CS4231 chip
    mpu_irq	- IRQ # for MPU-401 UART
    dma1	- first DMA # for CS4231 chip
    dma2	- second DMA # for CS4231 chip
    
    Module supports up to 8 cards. This module does not support autoprobe
    thus main port must be specified!!! Other ports are optional.

    The power-management is supported.
    
  Module snd-cs4232
  -----------------

    Module for sound cards based on CS4232/CS4232A ISA chips.

    port	- port # for CS4232 chip (PnP setup - 0x534)
    cport	- control port # for CS4232 chip (PnP setup - 0x120,0x210,0xf00)
    mpu_port	- port # for MPU-401 UART (PnP setup - 0x300), -1 = disable
    fm_port	- FM port # for CS4232 chip (PnP setup - 0x388), -1 = disable
    irq		- IRQ # for CS4232 chip (5,7,9,11,12,15)
    mpu_irq	- IRQ # for MPU-401 UART (9,11,12,15)
    dma1	- first DMA # for CS4232 chip (0,1,3)
    dma2	- second DMA # for Yamaha CS4232 chip (0,1,3), -1 = disable
    isapnp	- ISA PnP detection - 0 = disable, 1 = enable (default)
    
    Module supports up to 8 cards. This module does not support autoprobe
    thus main port must be specified!!! Other ports are optional.

    The power-management is supported.
    
  Module snd-cs4236
  -----------------

    Module for sound cards based on CS4235/CS4236/CS4236B/CS4237B/
                                   CS4238B/CS4239 ISA chips.

    port	- port # for CS4236 chip (PnP setup - 0x534)
    cport	- control port # for CS4236 chip (PnP setup - 0x120,0x210,0xf00)
    mpu_port	- port # for MPU-401 UART (PnP setup - 0x300), -1 = disable
    fm_port	- FM port # for CS4236 chip (PnP setup - 0x388), -1 = disable
    irq		- IRQ # for CS4236 chip (5,7,9,11,12,15)
    mpu_irq	- IRQ # for MPU-401 UART (9,11,12,15)
    dma1	- first DMA # for CS4236 chip (0,1,3)
    dma2	- second DMA # for CS4236 chip (0,1,3), -1 = disable
    isapnp	- ISA PnP detection - 0 = disable, 1 = enable (default)
    
    Module supports up to 8 cards. This module does not support autoprobe
    (if ISA PnP is not used) thus main port and control port must be
    specified!!! Other ports are optional.

    The power-management is supported.

  Module snd-cs4281
  -----------------

    Module for Cirrus Logic CS4281 soundchip.

    dual_codec	- Secondary codec ID (0 = disable, default)

    Module supports up to 8 cards.

    The power-management is supported.

  Module snd-cs46xx
  -----------------

    Module for PCI sound cards based on CS4610/CS4612/CS4614/CS4615/CS4622/
				       CS4624/CS4630/CS4280 PCI chips.

    external_amp     - Force to enable external amplifier.
    thinkpad         - Force to enable Thinkpad's CLKRUN control.
    mmap_valid       - Support OSS mmap mode (default = 0).

    Module supports up to 8 cards and autoprobe.
    Usually external amp and CLKRUN controls are detected automatically
    from PCI sub vendor/device ids.  If they don't work, give the options
    above explicitly.

    The power-management is supported.