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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20121226045355.GB13024@1.21jiggawatts.net>
Date:	Wed, 26 Dec 2012 15:53:55 +1100
From:	Thomas Karpiniec <tk@...1jiggawatts.net>
To:	alsa-devel@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Prevent loss of state between MIDI subscriptions

Apologies for the linewrap. This will be better:

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/