[LAD] alsa seq client ids??

Clemens Ladisch cladisch at fastmail.net
Wed Sep 12 15:08:42 UTC 2007

> On Wednesday 12 September 2007 14:00, IOhannes M zmoelnig wrote:
> > however i have found no way to find out, which clients are real midi
> > devices and which are not.

If your alsa-lib is new enough, you can try to check for

Chris Cannam wrote:
> A user application therefore couldn't rely on the alsalib version number
> when trying to decide whether a client numbered 16 to 63 was system or
> hardware.

And there's userspace drivers for Bluetooth and Firewire.

> I assume it must be intended that ALSA applications treat these numbers as 
> meaningless opaque identifiers; otherwise they wouldn't have been changed so 
> lightly.


> But I don't see any alternative if you want to do autoconnection 
> (even under user control).  Many people here will argue that autoconnection 
> is a bad idea in itself.

On my old SB-compatible card, opening the MIDI port will disable the
PCM device (or fail if the PCM is opened).

And what would the purpose be of automatically connecting to all
those ports, when there's more than one?
$ aplaymidi -l
 Port    Client name                      Port name
 14:0    Midi Through                     Midi Through Port-0
 14:1    Midi Through                     Midi Through Port-1
 20:0    MPU-401 UART MIDI                MPU-401 UART MIDI
 24:0    Yamaha DS-1E (YMF754) MIDI       Yamaha DS-1E (YMF754) MIDI
 25:0    OPL3 FM synth                    OPL3 FM Port
 32:0    SC-8820                          SC-8820 Part A
 32:1    SC-8820                          SC-8820 Part B
 32:2    SC-8820                          SC-8820 MIDI
 40:0    Virtual Raw MIDI 6-0             VirMIDI 6-0
 41:0    Virtual Raw MIDI 6-1             VirMIDI 6-1
 42:0    Virtual Raw MIDI 6-2             VirMIDI 6-2
 43:0    Virtual Raw MIDI 6-3             VirMIDI 6-3
 48:0    UM-2                             UM-2 MIDI 1
 48:1    UM-2                             UM-2 MIDI 2
 56:0    EMU10K1 MPU-401 (UART)           EMU10K1 MPU-401 (UART)
 57:0    Emu10k1 WaveTable                Emu10k1 Port 0
 57:1    Emu10k1 WaveTable                Emu10k1 Port 1
 57:2    Emu10k1 WaveTable                Emu10k1 Port 2
 57:3    Emu10k1 WaveTable                Emu10k1 Port 3
 60:0    Serial MIDI                      Serial MIDI 1
 64:0    C-Media CMI8738-MC8              C-Media CMI8738-MC8 MIDI
(yes, I'm bragging :-)

> Also, note that you can't rely on the SND_SEQ_PORT_TYPE flags to tell you 
> anything useful either.

They're strictly optional, but at least all the drivers set them.
(Both the in-the-kernel-but-virtual drivers, snd-virmidi and snd-seq-dummy,


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