linux-kernel - [PATCH] Prevent loss of state between MIDI subscriptions

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Date:	Wed, 26 Dec 2012 15:20:32 +1100
From:	Thomas Karpiniec <tk@...1jiggawatts.net>
To:	alsa-devel@...r.kernel.org
CC:	linux-kernel@...r.kernel.org
Subject: [PATCH] Prevent loss of state between MIDI subscriptions

A MIDI input parser is unnecessarily reset whenever a new subscription 
is created.

This is a particular problem with the Novation Launchpad, which sends a 
single NOTEON command, then a series of notes indefinitely unless a 
control button is pressed or it is power cycled. If a user application 
restarts and resubscribes, the parser no longer knows that it is 
receiving NOTEONs and fails to pass on new input.

Signed-off-by: Thomas Karpiniec <tk@...1jiggawatts.net>
---
  sound/core/seq/seq_midi.c |    1 -
  1 file changed, 1 deletion(-)

diff --git a/sound/core/seq/seq_midi.c b/sound/core/seq/seq_midi.c
index 64069db..1a977df 100644
--- a/sound/core/seq/seq_midi.c
+++ b/sound/core/seq/seq_midi.c
@@ -200,7 +200,6 @@ static int midisynth_subscribe(void *private_data, 
struct snd_seq_port_subscribe
  		snd_rawmidi_kernel_release(&msynth->input_rfile);
  		return err;
  	}
-	snd_midi_event_reset_encode(msynth->parser);
  	runtime->event = snd_midi_input_event;
  	runtime->private_data = msynth;
  	snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);
-- 
1.7.10.4
--
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