Full functionality has been added to the driver. Since some of the controls and startup-options are ALSA-Standard, only the special controls are described and discussed below.

ALSA philosopy is, that in low level driver only hardware features are implemented and all of them if possible, so i also listed some features which are not implemented since in conflict with other ALSA functionality for discussion only.

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 interface mixer.

double speed

1..32 channels

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 drive interface.

quad speed

1..16 channels

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 interface, so channel count for the driver

format

signed 32 Bit Little Endian (SNDRV_PCM_FMTBIT_S32_LE)

This is the only format for Hardware access suported by the card.

sample rates --

single speed

32000, 44100, 48000

double speed

64000, 88200, 96000 (untested, please report)

quad speed

128000, 176400, 192000 (untested, please report)

access-mode

MMAP (memory mapped), Not interleaved (PCM_NON-INTERLEAVED)

only supported hw access

buffer-sizes

64,128,256,512,1024,2048,8192 Samples

fragments

2

hardware-pointer

2 modi

The Card supports the readout of the actual bufferpointer of the DMA reads/writes. Since of the bulk mode of PCI it is only 64 Words accurate, it is not really usable for the ALSA-mid-level functions (here the buffer-id, which says in which half of the buffer the pointer is, gives a better result). But if MMAP is used by the application, the user application can use the more rpecise pointer for their purpose, dealing with the 64 Word inaccuracy. Therefore it can be configured at load-time with the parameter precise-pointer.

(Hint: Experimenting with it, 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.

control interface:

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 here !!!

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, even it had been at previous hammerfall interfaces.

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

Name

"Mixer"

Access

Read Write

Values -

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.

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 !!! maybe I implement it for special applications, but not officially

Module 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).

(translated from German, so no good English ;-), please comment

1. - winfried ritsch