[linux-audio-user] Please explain Alsa Interface MIDI numbering PLEASE!

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Subject: [linux-audio-user] Please explain Alsa Interface MIDI numbering PLEASE!
From: Mark Knecht (markknecht_AT_attbi.com)
Date: Sun Feb 16 2003 - 20:52:23 EET

Hi,
   I'm having a great deal of confusion about how Alsa is handling my
MIDI hardware. This is spilling over into unintended consequences in
Rosegarden that I think none of us understand. Couple someone with some
background in this please explain? Thanks.

   I have two 2-port MIDI devices on this system. One is an RME HDSP
9652 with two MIDI ports, and the other is a hot pluggable MidiSport
2x2. I attach two screen shots of kaconnect, one with and one without
the 2x2 plugged in.

   My questions:

1) In the screen shot "without_2x2.png" I see two read ports and two
write ports. Please explain why they are called

64:0 External MIDI 0
64:32 External MIDI 0

Why is my HDSP given the apparent name '64'? Why the :0 and :32? I would
have thought :0 and :16 would make more sense from a channel numbering
point of view, or :0 and :1 from an interface point of view. What's
going on?

2) In the screen shot "with_2x2.png" I've plugged in the MidiSport 2x2.
New devices show up in kaconnect. However, instead of showing 2 read
ports and 2 write ports, I am getting 4 read ports and no write ports.
Please explain why the MidiSport is given the names

72:0 External MIDI 1
72:1 External MIDI 1
72:2 External MIDI 1
72:3 External MIDI 1

Shouldn't this be just :0 and :1 for both the read and write ports?

I get the feeling that BOTH of the drivers for these devices are hosed.
What's up with these things?

   I do not understand why Alsa gives these devices numbers in the first
place, nor how the numbers are assigned.

   How can I change the names that are displayed so that

"64:0 External MIDI 0" shows the name "HDSP 9652 Port 1"

"64:32 External MIDI 0" shows the name "HDSP 9652 Port 2"

"72:0 External MIDI 1" shows the name "MidiSport 2x2 Port A"

"72:1 External MIDI 1" shows the name "MidiSport 2x2 Port B"

Thanks very, very much in advance,
Mark

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