mirror of https://gitee.com/openkylin/linux.git
101 lines
3.2 KiB
Plaintext
101 lines
3.2 KiB
Plaintext
Alsa driver for Digigram miXart8 and miXart8AES/EBU soundcards
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Digigram <alsa@digigram.com>
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GENERAL
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=======
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The miXart8 is a multichannel audio processing and mixing soundcard
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that has 4 stereo audio inputs and 4 stereo audio outputs.
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The miXart8AES/EBU is the same with a add-on card that offers further
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4 digital stereo audio inputs and outputs.
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Furthermore the add-on card offers external clock synchronisation
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(AES/EBU, Word Clock, Time Code and Video Synchro)
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The mainboard has a PowerPC that offers onboard mpeg encoding and
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decoding, samplerate conversions and various effects.
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The driver don't work properly at all until the certain firmwares
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are loaded, i.e. no PCM nor mixer devices will appear.
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Use the mixartloader that can be found in the alsa-tools package.
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VERSION 0.1.0
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=============
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One miXart8 board will be represented as 4 alsa cards, each with 1
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stereo analog capture 'pcm0c' and 1 stereo analog playback 'pcm0p' device.
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With a miXart8AES/EBU there is in addition 1 stereo digital input
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'pcm1c' and 1 stereo digital output 'pcm1p' per card.
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Formats
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-------
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U8, S16_LE, S16_BE, S24_3LE, S24_3BE, FLOAT_LE, FLOAT_BE
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Sample rates : 8000 - 48000 Hz continuously
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Playback
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--------
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For instance the playback devices are configured to have max. 4
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substreams performing hardware mixing. This could be changed to a
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maximum of 24 substreams if wished.
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Mono files will be played on the left and right channel. Each channel
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can be muted for each stream to use 8 analog/digital outputs separately.
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Capture
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-------
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There is one substream per capture device. For instance only stereo
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formats are supported.
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Mixer
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-----
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<Master> and <Master Capture> : analog volume control of playback and capture PCM.
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<PCM 0-3> and <PCM Capture> : digital volume control of each analog substream.
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<AES 0-3> and <AES Capture> : digital volume control of each AES/EBU substream.
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<Monitoring> : Loopback from 'pcm0c' to 'pcm0p' with digital volume
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and mute control.
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Rem : for best audio quality try to keep a 0 attenuation on the PCM
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and AES volume controls which is set by 219 in the range from 0 to 255
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(about 86% with alsamixer)
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NOT YET IMPLEMENTED
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===================
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- external clock support (AES/EBU, Word Clock, Time Code, Video Sync)
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- MPEG audio formats
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- mono record
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- on-board effects and samplerate conversions
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- linked streams
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FIRMWARE
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========
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[As of 2.6.11, the firmware can be loaded automatically with hotplug
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when CONFIG_FW_LOADER is set. The mixartloader is necessary only
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for older versions or when you build the driver into kernel.]
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For loading the firmware automatically after the module is loaded, use a
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install command. For example, add the following entry to
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/etc/modprobe.d/mixart.conf for miXart driver:
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install snd-mixart /sbin/modprobe --first-time -i snd-mixart && \
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/usr/bin/mixartloader
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(for 2.2/2.4 kernels, add "post-install snd-mixart /usr/bin/vxloader" to
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/etc/modules.conf, instead.)
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The firmware binaries are installed on /usr/share/alsa/firmware
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(or /usr/local/share/alsa/firmware, depending to the prefix option of
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configure). There will be a miXart.conf file, which define the dsp image
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files.
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The firmware files are copyright by Digigram SA
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COPYRIGHT
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=========
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Copyright (c) 2003 Digigram SA <alsa@digigram.com>
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Distributable under GPL.
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