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ALSA: emu10k1: add separate documentation for E-MU cards
They are sufficiently different from Sound Blasters. Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de> Link: https://lore.kernel.org/r/20230825222157.170978-3-oswald.buddenhagen@gmx.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
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‎Documentation/sound/cards/emu-mixer.rst

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==================================================
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E-MU Digital Audio System mixer / default DSP code
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==================================================
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This document covers the E-MU 0404/1010/1212/1616/1820 PCI/PCI-e/CardBus
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cards.
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These cards use regular EMU10K2 (SoundBlaster Audigy) chips, but with an
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alternative front-end geared towards semi-professional studio recording.
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This document is based on audigy-mixer.rst.
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Hardware compatibility
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======================
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The EMU10K2 chips have a very short capture FIFO, which makes recording
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unreliable if the card's PCI bus requests are not handled with the
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appropriate priority.
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This is the case on more modern motherboards, where the PCI bus is only a
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secondary peripheral, rather than the actual arbiter of device access.
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In particular, I got recording glitches during simultaneous playback on an
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Intel DP55 board (memory controller in the CPU), but had success with an
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Intel DP45 board (memory controller in the north bridge).
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The PCI Express variants of these cards (which have a PCI bridge on board,
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but are otherwise identical) may be less problematic.
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Driver capabilities
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===================
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This driver supports only 16-bit 44.1/48 kHz operation. The multi-channel
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device (see emu10k1-jack.rst) additionally supports 24-bit capture.
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A patchset to enhance the driver is available from `a GitHub repository
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<https://github.com/ossilator/linux/tree/ossis-emu10k1>`_.
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Its multi-channel device supports 24-bit for both playback and capture,
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and also supports full 88.2/96/176.4/192 kHz operation.
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It is not going to be upstreamed due to a fundamental disagreement about
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what constitutes a good user experience.
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Digital mixer controls
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======================
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Note that the controls work as attenuators: the maximum value is the neutral
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position leaving the signal unchanged. Note that if the same destination is
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mentioned in multiple controls, the signal is accumulated and can be clipped
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(set to maximal or minimal value without checking for overflow).
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Explanation of used abbreviations:
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DAC
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digital to analog converter
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ADC
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analog to digital converter
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LFE
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low frequency effects (used as subwoofer signal)
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IEC958
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S/PDIF
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FX-bus
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the EMU10K2 chip has an effect bus containing 64 accumulators.
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Each of the synthesizer voices can feed its output to these accumulators
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and the DSP microcontroller can operate with the resulting sum.
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name='Clock Source',index=0
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---------------------------
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This control allows switching the word clock between interally generated
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44.1 or 48 kHz, or a number of external sources.
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Note: the sources for the 1616 CardBus card are unclear. Please report your
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findings.
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name='Clock Fallback',index=0
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-----------------------------
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This control determines the internal clock which the card switches to when
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the selected external clock source is/becomes invalid.
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name='DAC1 0202 14dB PAD',index=0, etc.
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---------------------------------------
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Output attenuation controls. Not available on 0404 cards.
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name='ADC1 14dB PAD 0202',index=0, etc.
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---------------------------------------
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Input attenuation controls. Not available on 0404 cards.
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name='Optical Output Mode',index=0
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----------------------------------
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Switches the TOSLINK output port between S/PDIF and ADAT.
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Not available on 0404 cards (fixed to S/PDIF).
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name='Optical Input Mode',index=0
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---------------------------------
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Switches the TOSLINK input port between S/PDIF and ADAT.
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Not available on 0404 cards (fixed to S/PDIF).
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name='PCM Front Playback Volume',index=0
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----------------------------------------
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This control is used to attenuate samples from left and right front PCM FX-bus
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accumulators. ALSA uses accumulators 8 and 9 for left and right front PCM
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samples for 5.1 playback. The result samples are forwarded to the DSP 0 & 1
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playback channels.
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name='PCM Surround Playback Volume',index=0
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-------------------------------------------
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This control is used to attenuate samples from left and right surround PCM FX-bus
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accumulators. ALSA uses accumulators 2 and 3 for left and right surround PCM
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samples for 5.1 playback. The result samples are forwarded to the DSP 2 & 3
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playback channels.
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name='PCM Side Playback Volume',index=0
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---------------------------------------
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This control is used to attenuate samples from left and right side PCM FX-bus
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accumulators. ALSA uses accumulators 14 and 15 for left and right side PCM
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samples for 7.1 playback. The result samples are forwarded to the DSP 6 & 7
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playback channels.
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name='PCM Center Playback Volume',index=0
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-----------------------------------------
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This control is used to attenuate samples from the center PCM FX-bus accumulator.
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ALSA uses accumulator 6 for center PCM samples for 5.1 playback. The result samples
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are forwarded to the DSP 4 playback channel.
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name='PCM LFE Playback Volume',index=0
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--------------------------------------
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This control is used to attenuate samples from the LFE PCM FX-bus accumulator.
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ALSA uses accumulator 7 for LFE PCM samples for 5.1 playback. The result samples
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are forwarded to the DSP 5 playback channel.
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name='PCM Playback Volume',index=0
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----------------------------------
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This control is used to attenuate samples from left and right PCM FX-bus
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accumulators. ALSA uses accumulators 0 and 1 for left and right PCM samples for
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stereo playback. The result samples are forwarded to the virtual stereo mixer.
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name='PCM Capture Volume',index=0
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---------------------------------
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This control is used to attenuate samples from left and right PCM FX-bus
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accumulators. ALSA uses accumulators 0 and 1 for left and right PCM.
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The result is forwarded to the standard capture PCM device.
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name='Music Playback Volume',index=0
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------------------------------------
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This control is used to attenuate samples from left and right MIDI FX-bus
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accumulators. ALSA uses accumulators 4 and 5 for left and right MIDI samples.
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The result samples are forwarded to the virtual stereo mixer.
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name='Music Capture Volume',index=0
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-----------------------------------
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These controls are used to attenuate samples from left and right MIDI FX-bus
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accumulator. ALSA uses accumulators 4 and 5 for left and right MIDI samples.
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The result is forwarded to the standard capture PCM device.
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name='Front Playback Volume',index=0
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------------------------------------
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This control is used to attenuate samples from the virtual stereo mixer.
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The result samples are forwarded to the DSP 0 & 1 playback channels.
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name='Surround Playback Volume',index=0
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---------------------------------------
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This control is used to attenuate samples from the virtual stereo mixer.
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The result samples are forwarded to the DSP 2 & 3 playback channels.
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name='Side Playback Volume',index=0
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-----------------------------------
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This control is used to attenuate samples from the virtual stereo mixer.
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The result samples are forwarded to the DSP 6 & 7 playback channels.
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name='Center Playback Volume',index=0
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-------------------------------------
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This control is used to attenuate samples from the virtual stereo mixer.
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The result samples are forwarded to the DSP 4 playback channel.
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name='LFE Playback Volume',index=0
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----------------------------------
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This control is used to attenuate samples from the virtual stereo mixer.
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The result samples are forwarded to the DSP 5 playback channel.
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name='Tone Control - Switch',index=0
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------------------------------------
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This control turns the tone control on or off. The samples forwarded to
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the DSP playback channels are affected.
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name='Tone Control - Bass',index=0
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----------------------------------
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This control sets the bass intensity. There is no neutral value!!
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When the tone control code is activated, the samples are always modified.
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The closest value to pure signal is 20.
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name='Tone Control - Treble',index=0
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------------------------------------
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This control sets the treble intensity. There is no neutral value!!
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When the tone control code is activated, the samples are always modified.
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The closest value to pure signal is 20.
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name='Master Playback Volume',index=0
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-------------------------------------
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This control is used to attenuate samples for all DSP playback channels.
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name='EMU Capture Volume',index=0
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----------------------------------
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This control is used to attenuate samples from the DSP 0 & 1 capture channels.
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The result is forwarded to the standard capture PCM device.
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name='DAC Left',index=0, etc.
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-----------------------------
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Select the source for the given physical audio output. These may be physical
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inputs, playback channels (DSP xx, specified as a decimal number), or silence.
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name='DSP x',index=0
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--------------------
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Select the source for the given capture channel (specified as a hexadecimal
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digit). Same options as for the physical audio outputs.
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PCM stream related controls
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===========================
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These controls are described in audigy-mixer.rst.
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MANUALS/PATENTS
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===============
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See sb-live-mixer.rst.

‎Documentation/sound/cards/index.rst

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cmipci
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sb-live-mixer
1010
audigy-mixer
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emu-mixer
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emu10k1-jack
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via82xx-mixer
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audiophile-usb

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