From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH v5 04/10] ALSA: usb: update trigger timestamp on first non-zero URB submitted Date: Mon, 09 Feb 2015 16:06:21 +0100 Message-ID: References: <1423259759-4100-1-git-send-email-pierre-louis.bossart@linux.intel.com> <1423259759-4100-5-git-send-email-pierre-louis.bossart@linux.intel.com> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id 6CF842604A4 for ; Mon, 9 Feb 2015 16:06:22 +0100 (CET) In-Reply-To: <1423259759-4100-5-git-send-email-pierre-louis.bossart@linux.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Pierre-Louis Bossart Cc: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org At Fri, 6 Feb 2015 15:55:53 -0600, Pierre-Louis Bossart wrote: > > The first URBs are submitted during the prepare stage. When .trigger is > called, the ALSA core saves a trigger tstamp that doesn't correspond to > the actual time when the samples are submitted. The trigger_tstamp is > now updated when the first data are submitted to avoid any time offsets. > > A usb-specific trigger_tstamp_pending_update flag is used for now, > at some point the flag would need to move to the ALSA core, USB > is not the only interface where silent block transfers are programmed > as part of the prepare stage, with actual data enabled when .trigger > is called. > > Signed-off-by: Pierre-Louis Bossart Applied, thanks. Takashi > --- > sound/usb/card.h | 2 ++ > sound/usb/pcm.c | 9 +++++++++ > 2 files changed, 11 insertions(+) > > diff --git a/sound/usb/card.h b/sound/usb/card.h > index 97acb90..ef580b4 100644 > --- a/sound/usb/card.h > +++ b/sound/usb/card.h > @@ -153,6 +153,8 @@ struct snd_usb_substream { > int channel; > int byte_idx; > } dsd_dop; > + > + bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */ > }; > > struct snd_usb_stream { > diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c > index 0d8aba5..b4ef410 100644 > --- a/sound/usb/pcm.c > +++ b/sound/usb/pcm.c > @@ -1464,6 +1464,14 @@ static void prepare_playback_urb(struct snd_usb_substream *subs, > subs->last_frame_number = usb_get_current_frame_number(subs->dev); > subs->last_frame_number &= 0xFF; /* keep 8 LSBs */ > > + if (subs->trigger_tstamp_pending_update) { > + /* this is the first actual URB submitted, > + * update trigger timestamp to reflect actual start time > + */ > + snd_pcm_gettime(runtime, &runtime->trigger_tstamp); > + subs->trigger_tstamp_pending_update = false; > + } > + > spin_unlock_irqrestore(&subs->lock, flags); > urb->transfer_buffer_length = bytes; > if (period_elapsed) > @@ -1550,6 +1558,7 @@ static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substrea > > switch (cmd) { > case SNDRV_PCM_TRIGGER_START: > + subs->trigger_tstamp_pending_update = true; > case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: > subs->data_endpoint->prepare_data_urb = prepare_playback_urb; > subs->data_endpoint->retire_data_urb = retire_playback_urb; > -- > 1.9.1 > > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@alsa-project.org > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel >