[alsa-devel] No stream timing info with alsa pulse plugin?

[Arun Raghavan]

On 3 February 2015 at 07:10, Raymond Yau <superquad.vortex2 at gmail.com> wrote:
> 2015-1-27 上午3:33 於 "sqweek" <sqweek at gmail.com> 寫道：
>>
>> Hi guys,
>>
>> I discovered on my machine that alsa_snd_pcm_status_get_tstamp (and
>> also get_htstamp) stop working when my asoundrc invokes the pulse
>> plugin.
>>
>> That is, normally they work fine but once the sound is going via pulse
>> the returned time stamp is always zero. I'm trying to understand why
>> that is.
>>
>> I couldn't really find any discussion of the pulse plugin on the
>> archives so I'm not entirely sure I've found the right list; I was
>> directed here via the pulseaudio bugzilla[1].
>>
>> [1] https://bugs.freedesktop.org/show_bug.cgi?id=88503
>>
>
> http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=65ff6fdafb705b5e2e6d4b9a94a80e5de89f5de1;hp=9b716075de4f2f7f15e428ee7efaa8960ef45b9c#patch14
> 448,7 +448,7 @@ static int snd_pcm_ioplug_start(snd_pcm_t *pcm)
>         if (err < 0)
>                 return err;
>
> -       gettimestamp(&io->trigger_tstamp, pcm->monotonic);
> +       gettimestamp(&io->trigger_tstamp, pcm->tstamp_type);
>         io->data->state = SND_PCM_STATE_RUNNING;
>
>         return 0;
> @@ -463,7 +463,7 @@ static int snd_pcm_ioplug_drop(snd_pcm_t *pcm)
>
>         io->data->callback->stop(io->data);
>
> -       gettimestamp(&io->trigger_tstamp, pcm->monotonic);
> +       gettimestamp(&io->trigger_tstamp, pcm->tstamp_type);
>         io->data->state = SND_PCM_STATE_SETUP;
>
>         return 0;
> @@ -1069,7 +1069,10 @@ int snd_pcm_ioplug_reinit_status(snd_pcm_ioplug_t
> *ioplug)
> {
>         ioplug->pcm->poll_fd = ioplug->poll_fd;
>         ioplug->pcm->poll_events = ioplug->poll_events;
> -       ioplug->pcm->monotonic = (ioplug->flags &
> SND_PCM_IOPLUG_FLAG_MONOTONIC) != 0;
> +       if (ioplug->flags & SND_PCM_IOPLUG_FLAG_MONOTONIC)
> +               ioplug->pcm->tstamp_type = SND_PCM_TSTAMP_TYPE_MONOTONIC;
> +       else
> +               ioplug->pcm->tstamp_type = SND_PCM_TSTAMP_TYPE_GETTIMEOFDAY;
>         ioplug->pcm->mmap_rw = ioplug->mmap_rw;
>         return 0;
> }
>
> Although time stamp was enabled in pcm_ioplug.c , it does not implies all
> those io plugin really support time stamp
>
> Is this a bug ?

Seems to be. Takashi, others -- do have suggestions on how to handle this?

Regards,
Arun