From: Raymond Yau <superquad.vortex2@gmail.com>
To: Takashi Iwai <tiwai@suse.de>
Cc: ALSA Development Mailing List <alsa-devel@alsa-project.org>,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Subject: Re: [RFC PATCH 2/4] ALSA: core: add .notify callback for pcm ops
Date: Thu, 9 Jul 2015 15:25:58 +0800 [thread overview]
Message-ID: <CAN8cciYNQNXNzLgfFt=eXy4BVvYJaYfPPdwaCPUOJmuZO38LkQ@mail.gmail.com> (raw)
In-Reply-To: <s5hlheqhghu.wl-tiwai@suse.de>
> >
> > When appl_ptr is updated let low-level driver know.
> >
> > This is only enabled when the NO_REWIND hardware flag is used,
> > so that the low-level driver/hardware to opportunistically pre-fetch
> > data.
> >
> > FIXME: should we rely on .ack for this?
> > Signed-off-by: Pierre-Louis Bossart <
pierre-louis.bossart@linux.intel.com>
>
> Hmm, OK, so the forward is allowed but with workarounds...
> But then why rewind won't work in a similar way? DSP might be able to
> cancel some of inflight data.
>
> In other words, I see no reason to strict notify callback only for
> no_rewinds. This is an optional ops in anyway.
>
> Also, I find the name "notify" a bit too ambiguous. In this case,
> it's notifying the applptr change. So, a name related with the
> function would be more understandable.
>
>
If driver specify no rewind flag, should alsa lib
1) return error when application call snd_pcm_rewind() and
snd_pcm_forward() ?
2) return zero when call snd_pcm_rewindable() and snd_pcm_forwardable()
How can the application recover when hw_ptr is behind appl_ptr when stop
threshold is set to boundary ?
Do you mean compressed audio stream don't support rewind and forward ?
next prev parent reply other threads:[~2015-07-09 7:26 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-08 10:10 [RFC PATCH 0/4] better support for bursty DMA usages Pierre-Louis Bossart
2015-07-08 10:10 ` [RFC PATCH 1/4] ALSA: core: let low-level driver or userspace disable rewinds Pierre-Louis Bossart
2015-07-08 14:21 ` Takashi Iwai
2015-07-08 16:58 ` Pierre-Louis Bossart
2015-07-11 17:06 ` Alexander E. Patrakov
2015-07-14 3:32 ` Raymond Yau
2015-07-14 17:39 ` Alexander E. Patrakov
2015-07-15 1:23 ` Raymond Yau
2015-07-15 4:51 ` Alexander E. Patrakov
2015-07-28 14:19 ` Pierre-Louis Bossart
2015-07-28 15:43 ` Alexander E. Patrakov
2015-07-29 17:46 ` Pierre-Louis Bossart
2015-07-30 6:11 ` Alexander E. Patrakov
2015-07-30 13:46 ` Pierre-Louis Bossart
2015-07-08 10:10 ` [RFC PATCH 2/4] ALSA: core: add .notify callback for pcm ops Pierre-Louis Bossart
2015-07-08 14:27 ` Takashi Iwai
2015-07-08 17:10 ` Pierre-Louis Bossart
2015-07-09 14:44 ` Takashi Iwai
2015-07-09 7:25 ` Raymond Yau [this message]
2015-07-09 7:35 ` Pierre-Louis Bossart
2015-07-08 10:10 ` [RFC PATCH 3/4] ALSA: core: add report of max dma burst Pierre-Louis Bossart
2015-07-08 14:37 ` Takashi Iwai
2015-07-08 17:46 ` Pierre-Louis Bossart
2015-07-10 2:35 ` Raymond Yau
2015-07-10 17:13 ` Lars-Peter Clausen
2015-07-11 17:46 ` Alexander E. Patrakov
2015-07-11 18:28 ` Jaroslav Kysela
2015-07-16 2:11 ` Raymond Yau
2015-07-08 10:10 ` [RFC PATCH 4/4] ALSA: hda: add default value for max_dma_burst Pierre-Louis Bossart
2015-07-08 14:31 ` [RFC PATCH 0/4] better support for bursty DMA usages Takashi Iwai
2015-07-08 17:50 ` Pierre-Louis Bossart
2015-07-15 10:14 ` Raymond Yau
2015-07-15 10:38 ` Alexander E. Patrakov
2015-07-22 14:44 ` Raymond Yau
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