--- /dev/null
+Software Interface ALSA-DSP MADI Driver
+
+(translated from German, so no good English ;-),
+2004 - winfried ritsch
+
+
+
+ Full functionality has been added to the driver. Since some of
+ the Controls and startup-options are ALSA-Standard and only the
+ special Controls are described and discussed below.
+
+
+ hardware functionality:
+
+
+ Audio transmission:
+
+ number of channels -- depends on transmission mode
+
+ The number of channels chosen is from 1..Nmax. The reason to
+ use for a lower number of channels is only resource allocation,
+ since unused DMA channels are disabled and less memory is
+ allocated. So also the throughput of the PCI system can be
+ scaled. (Only important for low performance boards).
+
+ Single Speed -- 1..64 channels
+
+ (Note: Choosing the 56channel mode for transmission or as
+ receiver, only 56 are transmitted/received over the MADI, but
+ all 64 channels are available for the mixer, so channel count
+ for the driver)
+
+ Double Speed -- 1..32 channels
+
+ Note: Choosing the 56-channel mode for
+ transmission/receive-mode , only 28 are transmitted/received
+ over the MADI, but all 32 channels are available for the mixer,
+ so channel count for the driver
+
+
+ Quad Speed -- 1..16 channels
+
+ Note: Choosing the 56-channel mode for
+ transmission/receive-mode , only 14 are transmitted/received
+ over the MADI, but all 16 channels are available for the mixer,
+ so channel count for the driver
+
+ Format -- signed 32 Bit Little Endian (SNDRV_PCM_FMTBIT_S32_LE)
+
+ Sample Rates --
+
+ Single Speed -- 32000, 44100, 48000
+
+ Double Speed -- 64000, 88200, 96000 (untested)
+
+ Quad Speed -- 128000, 176400, 192000 (untested)
+
+ access-mode -- MMAP (memory mapped), Not interleaved
+ (PCM_NON-INTERLEAVED)
+
+ buffer-sizes -- 64,128,256,512,1024,2048,8192 Samples
+
+ fragments -- 2
+
+ Hardware-pointer -- 2 Modi
+
+
+ The Card supports the readout of the actual Buffer-pointer,
+ where DMA reads/writes. Since of the bulk mode of PCI it is only
+ 64 Byte accurate. SO it is not really usable for the
+ ALSA-mid-level functions (here the buffer-ID gives a better
+ result), but if MMAP is used by the application. Therefore it
+ can be configured at load-time with the parameter
+ precise-pointer.
+
+
+ (Hint: Experimenting I found that the pointer is maximum 64 to
+ large never to small. So if you subtract 64 you always have a
+ safe pointer for writing, which is used on this mode inside
+ ALSA. In theory now you can get now a latency as low as 16
+ Samples, which is a quarter of the interrupt possibilities.)
+
+ Precise Pointer -- off
+ interrupt used for pointer-calculation
+
+ Precise Pointer -- on
+ hardware pointer used.
+
+ Controller:
+
+
+ Since DSP-MADI-Mixer has 8152 Fader, it does not make sense to
+ use the standard mixer-controls, since this would break most of
+ (especially graphic) ALSA-Mixer GUIs. So Mixer control has be
+ provided by a 2-dimensional controller using the
+ hwdep-interface.
+
+ Also all 128+256 Peak and RMS-Meter can be accessed via the
+ hwdep-interface. Since it could be a performance problem always
+ copying and converting Peak and RMS-Levels even if you just need
+ one, I decided to export the hardware structure, so that of
+ needed some driver-guru can implement a memory-mapping of mixer
+ or peak-meters over ioctl, or also to do only copying and no
+ conversion. A test-application shows the usage of the controller.
+
+ Latency Controls --- not implemented !!!
+
+
+ Note: Within the windows-driver the latency is accessible of a
+ control-panel, but buffer-sizes are controlled with ALSA from
+ hwparams-calls and should not be changed in run-state, I did not
+ implement it here.
+
+
+ System Clock -- suspended !!!!
+
+ Name -- "System Clock Mode"
+
+ Access -- Read Write
+
+ Values -- "Master" "Slave"
+
+
+ !!!! This is a hardware-function but is in conflict with the
+ Clock-source controller, which is a kind of ALSA-standard. I
+ makes sense to set the card to a special mode (master at some
+ frequency or slave), since even not using an Audio-application
+ a studio should have working synchronisations setup. So use
+ Clock-source-controller instead !!!!
+
+ Clock Source
+
+ Name -- "Sample Clock Source"
+
+ Access -- Read Write
+
+ Values -- "AutoSync", "Internal 32.0 kHz", "Internal 44.1 kHz",
+ "Internal 48.0 kHz", "Internal 64.0 kHz", "Internal 88.2 kHz",
+ "Internal 96.0 kHz"
+
+ Choose between Master at a specific Frequency and so also the
+ Speed-mode or Slave (Autosync). Also see "Preferred Sync Ref"
+
+
+ !!!! This is no pure hardware function but was implemented by
+ ALSA by some ALSA-drivers before, so I use it also. !!!
+
+
+ Preferred Sync Ref
+
+ Name -- "Preferred Sync Reference"
+
+ Access -- Read Write
+
+ Values -- "Word" "MADI"
+
+
+ Within the Auto-sync-Mode the preferred Sync Source can be
+ chosen. If it is not available another is used if possible.
+
+ Note: Since MADI has a much higher bit-rate than word-clock, the
+ card should synchronise better in MADI Mode. But since the
+ RME-PLL is very good, there are almost no problems with
+ word-clock too. I never found a difference.
+
+
+ TX 64 channel ---
+
+ Name -- "TX 64 channels mode"
+
+ Access -- Read Write
+
+ Values -- 0 1
+
+ Using 64-channel-modus (1) or 56-channel-modus for
+ MADI-transmission (0).
+
+
+ Note: This control is for output only. Input-mode is detected
+ automatically from hardware sending MADI.
+
+
+ Clear TMS ---
+
+ Name -- "Clear Track Marker"
+
+ Access -- Read Write
+
+ Values -- 0 1
+
+
+ Don't use to lower 5 Audio-bits on AES as additional Bits.
+
+
+ Safe Mode oder Auto Input ---
+
+ Name -- "Safe Mode"
+
+ Access -- Read Write
+
+ Values -- 0 1
+
+ (default on)
+
+ If on (1), then if either the optical or coaxial connection
+ has a failure, there is a takeover to the working one, with no
+ sample failure. Its only useful if you use the second as a
+ backup connection.
+
+ Input ---
+
+ Name -- "Input Select"
+
+ Access -- Read Write
+
+ Values -- optical coaxial
+
+
+ Choosing the Input, optical or coaxial. If Safe-mode is active,
+ this is the preferred Input.
+
+-------------- Mixer ----------------------
+
+ Mixer
+
+ Name -- "Mixer"
+
+ Access -- Read Write
+
+ Values - <channel-number 0-127> <Value 0-65535>
+
+
+ Here as a first value the channel-index is taken to get/set the
+ corresponding mixer channel, where 0-63 are the input to output
+ fader and 64-127 the playback to outputs fader. Value 0
+ is channel muted 0 and 32768 an amplification of 1.
+
+ Chn 1-64
+
+ fast mixer for the ALSA-mixer utils. The diagonal of the
+ mixer-matrix is implemented from playback to output.
+
+
+ Line Out
+
+ Name -- "Line Out"
+
+ Access -- Read Write
+
+ Values -- 0 1
+
+ Switching on and off the analog out, which has nothing to do
+ with mixing or routing. the analog outs reflects channel 63,64.
+
+
+--- information (only read access):
+
+ Sample Rate
+
+ Name -- "System Sample Rate"
+
+ Access -- Read-only
+
+ getting the sample rate.
+
+
+ External Rate measured
+
+ Name -- "External Rate"
+
+ Access -- Read only
+
+
+ Should be "Autosync Rate", but Name used is
+ ALSA-Scheme. External Sample frequency liked used on Autosync is
+ reported.
+
+
+ MADI Sync Status
+
+ Name -- "MADI Sync Lock Status"
+
+ Access -- Read
+
+ Values -- 0,1,2
+
+ MADI-Input is 0=Unlocked, 1=Locked, or 2=Synced.
+
+
+ Word Clock Sync Status
+
+ Name -- "Word Clock Lock Status"
+
+ Access -- Read
+
+ Values -- 0,1,2
+
+ Word Clock Input is 0=Unlocked, 1=Locked, or 2=Synced.
+
+ AutoSync
+
+ Name -- "AutoSync Reference"
+
+ Access -- Read
+
+ Values -- "WordClock", "MADI", "None"
+
+ Sync-Reference is either "WordClock", "MADI" or none.
+
+ RX 64ch --- noch nicht implementiert
+
+ MADI-Receiver is in 64 channel mode oder 56 channel mode.
+
+
+ AB_inp --- not tested
+
+ Used input for Auto-Input.
+
+
+ actual Buffer Position --- not implemented
+
+ !!! this is a ALSA internal function, so no control is used !!!
+
+
+
+Calling Parameter:
+
+ index int array (min = 1, max = 8),
+ "Index value for RME HDSPM interface." card-index within ALSA
+
+ note: ALSA-standard
+
+ id string array (min = 1, max = 8),
+ "ID string for RME HDSPM interface."
+
+ note: ALSA-standard
+
+ enable int array (min = 1, max = 8),
+ "Enable/disable specific HDSPM sound-cards."
+
+ note: ALSA-standard
+
+ precise_ptr int array (min = 1, max = 8),
+ "Enable precise pointer, or disable."
+
+ note: Use only when the application supports this (which is a special case).
+
+ line_outs_monitor int array (min = 1, max = 8),
+ "Send playback streams to analog outs by default."
+
+
+ note: each playback channel is mixed to the same numbered output
+ channel (routed). This is against the ALSA-convention, where all
+ channels have to be muted on after loading the driver, but was
+ used before on other cards, so i historically use it again)
+
+
+
+ enable_monitor int array (min = 1, max = 8),
+ "Enable Analog Out on Channel 63/64 by default."
+
+ note: here the analog output is enabled (but not routed).
\ No newline at end of file
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