Date: Mon, 27 Feb 2006 13:13:19 +0100
Message-ID: <s5hek1pt2xs.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Junichi Uekawa <dancer@netfort.gr.jp>
Cc: alsa-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [Alsa-devel] [BUG] 2.6.16-rc4 git, ALSA USB-MIDI does not give NOTEOFF event for M-Audio Keystation 88es, but NOTEON with velocity=0
In-Reply-To: <87vev2w2hd.dancerj%dancer@netfort.gr.jp>
References: <87vev2w2hd.dancerj%dancer@netfort.gr.jp>
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At Mon, 27 Feb 2006 00:42:38 +0900,
Junichi Uekawa wrote:
> 
> Hi,
> 
> I'm seeing that USB MIDI keyboard (M-Audio Keystation 88es) is
> generating note-on events on both note-on and note-off. The difference
> being that note-off is generating an note-on event with velocity '0'.
> 
> The following code in seq_midi_emul.c(snd_midi_process_event) looks
> suspiciously like what's needed for this device:
> 
>         /* Make sure that we don't have a note on that should really be
>          * a note off */
>         if (ev->type == SNDRV_SEQ_EVENT_NOTEON && ev->data.note.velocity == 0)
>                 ev->type = SNDRV_SEQ_EVENT_NOTEOFF;

This code is irrelevant.  This is for MIDI emulation like emu10k1
WaveTable, not for the real MIDI device.

Basically the given behavior is not a bug.  The sequencer handles
note-on with velocity 0 as it is.  As a strict definition, note-off
and note-on with zero velocity are different although they are used
widely as identical in order to save bytes.


Takashi
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