From mboxrd@z Thu Jan  1 00:00:00 1970
From: Clemens Ladisch <clemens@ladisch.de>
Subject: Re: incoming sequencer event timestamping (via a
 running queue): how?
Date: Tue, 12 Apr 2011 07:49:26 +0200
Message-ID: <4DA3E7E6.7070801@ladisch.de>
References: <20110411200139.b9a035c0.chromisx@nedlinux.nl>
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To: "R. Dresens" <chromisx@nedlinux.nl>, r10kindsofpeople <r10kindsofpeople@gmail.com>
Cc: alsa-devel@alsa-project.org
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r10kindsofpeople wrote:
> On Mon, Apr 11, 2011 at 2:01 PM, R. Dresens <chromisx@nedlinux.nl> wrote:
> > At this moment, I just sample the tick value manually when I get an
> > event. That kinda works, but chances are high that the kernel
> > sequencer system can do that for me with more accuracy?
> 
> In your function that does the connection to the reception port...
> snd_seq_port_subscribe_set_queue(subs, queue_id);  //<< queue_id being the one you allocated
> snd_seq_port_subscribe_set_time_update(subs, 1);
> snd_seq_subscribe_port(pSeq, subs);

This is the correct way to get timestamps on events that go through
a subscription.

Alternatively, you can get timestamps on events that arrive at a port:
  snd_seq_port_info_set_timestamping(pinfo, 1);
  snd_seq_port_info_set_timestamp_queue(pinfo, queue);
  snd_seq_create_port(pSeq, pinfo);


Regards,
Clemens