From: Takashi Iwai <tiwai@suse.de>
To: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: alsa-devel@alsa-project.org
Subject: Re: [RFC PATCH 2/4] ALSA: core: add .notify callback for pcm ops
Date: Thu, 09 Jul 2015 16:44:01 +0200 [thread overview]
Message-ID: <s5hk2u9fl1q.wl-tiwai@suse.de> (raw)
In-Reply-To: <559D5988.70206@linux.intel.com>
On Wed, 08 Jul 2015 19:10:32 +0200,
Pierre-Louis Bossart wrote:
>
>
> >> 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.
>
> Nope, this is explicitly not supported, so unfortunately if we want to
> optimize for power and let hardware fetch data when it's most
> appropriate rewinds need to be disabled.
>
> > In other words, I see no reason to strict notify callback only for
> > no_rewinds. This is an optional ops in anyway.
>
> It's fine to remove the check. I added this based on internal review
> comments but I agree with your point.
OK, then let's treat the NO_REWIND and new ops individually.
> > 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.
>
> The first open I had was to know if we could use .ack for this? if a
> different callback is needed, we can use 'appl_ptr_update' instead of
> 'notify'
As there are no many users of ack callback, I don't mind to reuse it.
But then we need to extend the function to receive a new argument
indicating the type of ack, right?
thanks,
Takashi
next prev parent reply other threads:[~2015-07-09 14:44 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 [this message]
2015-07-09 7:25 ` Raymond Yau
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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