[PATCH] rawmidi.c Set a name for a newly allocated rawmidi substream

[PATCH] rawmidi.c Set a name for a newly allocated rawmidi substream

[Ralf Beck]

Rationale: Bitwig Studio (and possibly other rawmidi clients) enumerate 
the Midi I/Os by
substream names. With the current rawmidi implementation, the name is an 
empty string
and only the USB mididriver changes it to a meaningful value after 
allocation.

This patch sets a default substream name of the form "somename x-y-z"

--- linux-source-3.13.0/sound/core/rawmidi.c.orig    2014-05-06 
20:25:33.683081389 +0200
+++ linux-source-3.13.0/sound/core/rawmidi.c    2014-05-06 
17:42:35.058097185 +0200
@@ -34,6 +34,7 @@
  #include <sound/control.h>
  #include <sound/minors.h>
  #include <sound/initval.h>
+#include <linux/string.h>

  MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  MODULE_DESCRIPTION("Midlevel RawMidi code for ALSA.");
@@ -1420,6 +1421,8 @@ static int snd_rawmidi_alloc_substreams(
          substream->number = idx;
          substream->rmidi = rmidi;
          substream->pstr = stream;
+            snprintf(substream->name, sizeof(substream->name),
+                 "%s %d-%d-%d", rmidi->id, rmidi->card->number, 
rmidi->device, idx);
          list_add_tail(&substream->list, &stream->substreams);
          stream->substream_count++;
      }

Re: [PATCH] rawmidi.c Set a name for a newly allocated rawmidi substream

[Clemens Ladisch]

Ralf Beck wrote:
> Rationale: Bitwig Studio (and possibly other rawmidi clients) enumerate the Midi I/Os by
> substream names. With the current rawmidi implementation, the name is an empty string
> and only the USB mididriver changes it to a meaningful value after allocation.

Many RawMIDI devices have only one substream, or multiple substreams that are
merged into one port.  For these, separate substream names do not make sense.

> This patch sets a default substream name of the form "somename x-y-z"

The ID string is not meant to be a name.


Also see Documentation/SubmittingPatches.

> @@ -1420,6 +1421,8 @@ static int snd_rawmidi_alloc_substreams(
>          substream->number = idx;
>          substream->rmidi = rmidi;
>          substream->pstr = stream;
> +            snprintf(substream->name, sizeof(substream->name),

Your mailer broke whitespaces.


Regards,
Clemens

Re: [PATCH] rawmidi.c Set a name for a newly allocated rawmidi substream

[Ralf Beck]

Am 07.05.2014 19:39, schrieb Clemens Ladisch:
> Ralf Beck wrote:
>> Rationale: Bitwig Studio (and possibly other rawmidi clients) 
>> enumerate the Midi I/Os by substream names. With the current rawmidi 
>> implementation, the name is an empty string and only the USB 
>> mididriver changes it to a meaningful value after allocation. 
> Many RawMIDI devices have only one substream, or multiple substreams 
> that are merged into one port. For these, separate substream names do 
> not make sense. 
Any having no substream name at all makes more sense?
>> This patch sets a default substream name of the form "somename x-y-z" 
> The ID string is not meant to be a name. 
Would it be acceptable, if i remove the ID string and only return x-y-z ?
Other than the alsa developers i would call creating rawmidi substreams, 
but not
assigning a name to them a bug.

Best regards,
Ralf

Re: [PATCH] rawmidi.c Set a name for a newly allocated rawmidi substream

[Clemens Ladisch]

Ralf Beck wrote:
> Am 07.05.2014 19:39, schrieb Clemens Ladisch:
>> Ralf Beck wrote:
>>> Rationale: Bitwig Studio (and possibly other rawmidi clients) enumerate the Midi I/Os by substream names. With the current rawmidi implementation, the name is an empty string and only the USB mididriver changes it to a meaningful value after allocation.
>>
>> Many RawMIDI devices have only one substream, or multiple substreams that are merged into one port. For these, separate substream names do not make sense.
>
> Any having no substream name at all makes more sense?

The device itself already has a name.

Apparently, Bitwig has not been tested with any driver except snd-usb-audio.

>>> This patch sets a default substream name of the form "somename x-y-z"
>>
>> The ID string is not meant to be a name.
>
> Would it be acceptable, if i remove the ID string and only return x-y-z ?

No; you should use the device name or something like that.

But the substream name buffer is rather short; a better idea would be to
fix all rawmidi drivers to set the substream name(s) to the appropriate
value.

> Other than the alsa developers i would call creating rawmidi substreams, but not
> assigning a name to them a bug.

For most drivers, substreams do not have a logical identity separate
from the device.


Regards,
Clemens