From: Clemens Ladisch <clemens@ladisch.de>
To: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: alsa-devel@alsa-project.org
Subject: Re: [PATCH 1/2] ALSA: core: add hooks for audio timestamps
Date: Fri, 28 Sep 2012 11:33:50 +0200 [thread overview]
Message-ID: <50656EFE.40407@ladisch.de> (raw)
In-Reply-To: <1348820142-15822-1-git-send-email-pierre-louis.bossart@linux.intel.com>
Pierre-Louis Bossart wrote:
> @@ -506,8 +512,27 @@ static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
> + if (!(runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK)) {
> + /*
> + * no wall clock available, provide audio timestamp
> + * derived from pointer position+delay
> + */
> + u64 audio_frames, audio_nsecs;
> +
> + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> + audio_frames = runtime->status->hw_ptr
> + - runtime->delay;
> + else
> + audio_frames = runtime->status->hw_ptr
> + + runtime->delay;
> + audio_nsecs = audio_frames * 1000000000LL /
> + runtime->rate;
This looks like a 64-bit division.
And what happens if audio_frames becomes negative?
Regards,
Clemens
next prev parent reply other threads:[~2012-09-28 9:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-28 8:15 [PATCH 1/2] ALSA: core: add hooks for audio timestamps Pierre-Louis Bossart
2012-09-28 8:15 ` [PATCH 2/2] ALSA: hda: support for wallclock timestamps Pierre-Louis Bossart
2012-09-28 9:33 ` Clemens Ladisch
2012-09-29 20:12 ` Pierre-Louis Bossart
2012-09-30 10:12 ` Clemens Ladisch
2012-09-29 1:47 ` Raymond Yau
2012-09-28 9:33 ` Clemens Ladisch [this message]
2012-09-29 20:17 ` [PATCH 1/2] ALSA: core: add hooks for audio timestamps Pierre-Louis Bossart
2012-09-30 10:11 ` Clemens Ladisch
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