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docs: sound: hdspm: clean up driver doc.
Do some overall document cleanups: - add driver name for clarification - fix some punctuation issues - correct some capitalization - correct some grammar - convert a few words from German to English - eliminate double use of "note:" - unindent Precise Pointer bullets so that they are not part of the Hint - drop precise_ptr documentation since it has been modified to be "always on" Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: https://patch.msgid.link/20260914195806.1544938-1-rdunlap@infradead.org Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Randy Dunlap
Takashi Iwai
parent
c1d6580f70
commit
4d4bc65658
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@ -6,9 +6,11 @@ Software Interface ALSA-DSP MADI Driver
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2004 - winfried ritsch
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driver name - snd-hdspm
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Full functionality has been added to the driver. Since some of
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the Controls and startup-options are ALSA-Standard and only the
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the Controls and startup options are ALSA-Standard, only the
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special Controls are described and discussed below.
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@ -18,7 +20,7 @@ Hardware functionality
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Audio transmission
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------------------
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* number of channels -- depends on transmission mode
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* number of channels -- depends on transmission mode
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The number of channels chosen is from 1..Nmax. The reason to
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use for a lower number of channels is only resource allocation,
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@ -29,29 +31,29 @@ Audio transmission
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* Single Speed -- 1..64 channels
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.. note::
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(Note: Choosing the 56channel mode for transmission or as
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Choosing the 56-channel mode for transmission or as
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receiver, only 56 are transmitted/received over the MADI, but
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all 64 channels are available for the mixer, so channel count
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for the driver)
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for the driver.
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* Double Speed -- 1..32 channels
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.. note::
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Note: Choosing the 56-channel mode for
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transmission/receive-mode , only 28 are transmitted/received
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Choosing the 56-channel mode for
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transmission/receive-mode, only 28 are transmitted/received
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over the MADI, but all 32 channels are available for the mixer,
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so channel count for the driver
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so channel count for the driver.
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* Quad Speed -- 1..16 channels
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.. note::
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Choosing the 56-channel mode for
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transmission/receive-mode , only 14 are transmitted/received
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transmission/receive-mode, only 14 are transmitted/received
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over the MADI, but all 16 channels are available for the mixer,
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so channel count for the driver
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so channel count for the driver.
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* Format -- signed 32 Bit Little Endian (SNDRV_PCM_FMTBIT_S32_LE)
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* Format -- signed 32-bit Little Endian (SNDRV_PCM_FMTBIT_S32_LE)
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* Sample Rates --
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@ -67,30 +69,6 @@ Audio transmission
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* fragments -- 2
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* Hardware-pointer -- 2 Modi
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The Card supports the readout of the actual Buffer-pointer,
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where DMA reads/writes. Since of the bulk mode of PCI it is only
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64 Byte accurate. SO it is not really usable for the
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ALSA-mid-level functions (here the buffer-ID gives a better
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result), but if MMAP is used by the application. Therefore it
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can be configured at load-time with the parameter
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precise-pointer.
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.. hint::
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(Hint: Experimenting I found that the pointer is maximum 64 to
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large never to small. So if you subtract 64 you always have a
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safe pointer for writing, which is used on this mode inside
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ALSA. In theory now you can get now a latency as low as 16
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Samples, which is a quarter of the interrupt possibilities.)
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* Precise Pointer -- off
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interrupt used for pointer-calculation
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* Precise Pointer -- on
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hardware pointer used.
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Controller
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----------
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@ -104,7 +82,7 @@ hwdep-interface.
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Also all 128+256 Peak and RMS-Meter can be accessed via the
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hwdep-interface. Since it could be a performance problem always
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copying and converting Peak and RMS-Levels even if you just need
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one, I decided to export the hardware structure, so that of
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one, I decided to export the hardware structure, so that if
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needed some driver-guru can implement a memory-mapping of mixer
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or peak-meters over ioctl, or also to do only copying and no
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conversion. A test-application shows the usage of the controller.
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@ -112,9 +90,9 @@ conversion. A test-application shows the usage of the controller.
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* Latency Controls --- not implemented !!!
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.. note::
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Note: Within the windows-driver the latency is accessible of a
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control-panel, but buffer-sizes are controlled with ALSA from
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hwparams-calls and should not be changed in run-state, I did not
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Within the Windows driver the latency is accessible via
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Control Panel, but buffer sizes are controlled with ALSA from
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hwparams calls and should not be changed in run-state. I did not
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implement it here.
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@ -127,12 +105,12 @@ conversion. A test-application shows the usage of the controller.
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* Values -- "Master" "Slave"
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.. note::
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!!!! This is a hardware-function but is in conflict with the
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Clock-source controller, which is a kind of ALSA-standard. I
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!!!! This is a hardware function but is in conflict with the
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Clock-source controller, which is a kind of ALSA-standard. It
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makes sense to set the card to a special mode (master at some
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frequency or slave), since even not using an Audio-application
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frequency or slave), since even not using an Audio application
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a studio should have working synchronisations setup. So use
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Clock-source-controller instead !!!!
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Clock-source controller instead !!!!
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* Clock Source
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@ -145,11 +123,11 @@ conversion. A test-application shows the usage of the controller.
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"Internal 96.0 kHz"
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Choose between Master at a specific Frequency and so also the
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Speed-mode or Slave (Autosync). Also see "Preferred Sync Ref"
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Speed-mode or Slave (Autosync). Also see "Preferred Sync Ref".
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.. warning::
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!!!! This is no pure hardware function but was implemented by
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ALSA by some ALSA-drivers before, so I use it also. !!!
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!!!! This is not a pure hardware function but was implemented by
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ALSA by some ALSA drivers before, so I use it also. !!!
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* Preferred Sync Ref
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@ -165,7 +143,7 @@ conversion. A test-application shows the usage of the controller.
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chosen. If it is not available another is used if possible.
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.. note::
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Note: Since MADI has a much higher bit-rate than word-clock, the
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Since MADI has a much higher bit-rate than word-clock, the
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card should synchronise better in MADI Mode. But since the
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RME-PLL is very good, there are almost no problems with
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word-clock too. I never found a difference.
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@ -179,12 +157,12 @@ conversion. A test-application shows the usage of the controller.
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* Values -- 0 1
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Using 64-channel-modus (1) or 56-channel-modus for
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Using 64-channel mode (1) or 56-channel mode for
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MADI-transmission (0).
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.. note::
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Note: This control is for output only. Input-mode is detected
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This control is for output only. Input mode is detected
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automatically from hardware sending MADI.
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@ -200,7 +178,7 @@ conversion. A test-application shows the usage of the controller.
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Don't use to lower 5 Audio-bits on AES as additional Bits.
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* Safe Mode oder Auto Input
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* Safe Mode or Auto Input
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* Name -- "Safe Mode"
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@ -222,7 +200,7 @@ conversion. A test-application shows the usage of the controller.
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* Values -- optical coaxial
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Choosing the Input, optical or coaxial. If Safe-mode is active,
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Choosing the Input, optical or coaxial. If Safe mode is active,
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this is the preferred Input.
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Mixer
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@ -240,7 +218,7 @@ Mixer
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Here as a first value the channel-index is taken to get/set the
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corresponding mixer channel, where 0-63 are the input to output
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fader and 64-127 the playback to outputs fader. Value 0
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is channel muted 0 and 32768 an amplification of 1.
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is channel muted 0 and 32768 an amplification of 1.
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* Chn 1-64
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@ -250,14 +228,14 @@ Mixer
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* Line Out
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* Name -- "Line Out"
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* Name -- "Line Out"
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* Access -- Read Write
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* Values -- 0 1
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Switching on and off the analog out, which has nothing to do
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with mixing or routing. the analog outs reflects channel 63,64.
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with mixing or routing. The analog outs reflects channel 63,64.
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Information (only read access)
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@ -280,7 +258,7 @@ Information (only read access)
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Should be "Autosync Rate", but Name used is
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ALSA-Scheme. External Sample frequency liked used on Autosync is
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ALSA-Scheme. External Sample frequency like used on Autosync is
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reported.
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@ -315,19 +293,19 @@ Information (only read access)
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Sync-Reference is either "WordClock", "MADI" or none.
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* RX 64ch --- noch nicht implementiert
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* RX 64ch --- not yet implemented
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MADI-Receiver is in 64 channel mode oder 56 channel mode.
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MADI-Receiver is in 64-channel mode or 56-channel mode.
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* AB_inp --- not tested
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* AB_inp --- not tested
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Used input for Auto-Input.
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* actual Buffer Position --- not implemented
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!!! this is a ALSA internal function, so no control is used !!!
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!!! This is an ALSA internal function, so no control is used !!!
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@ -352,22 +330,15 @@ Calling Parameter
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note: ALSA-standard
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* precise_ptr int array (min = 1, max = 8)
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Enable precise pointer, or disable.
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.. note::
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note: Use only when the application supports this (which is a special case).
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* line_outs_monitor int array (min = 1, max = 8)
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Send playback streams to analog outs by default.
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.. note::
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note: each playback channel is mixed to the same numbered output
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Each playback channel is mixed to the same numbered output
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channel (routed). This is against the ALSA-convention, where all
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channels have to be muted on after loading the driver, but was
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used before on other cards, so i historically use it again)
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used before on other cards, so I historically use it again.
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@ -375,5 +346,5 @@ Calling Parameter
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Enable Analog Out on Channel 63/64 by default.
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.. note ::
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note: here the analog output is enabled (but not routed).
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.. note::
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Here the analog output is enabled (but not routed).
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