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From: Vinod Koul <vkoul@kernel.org>
To: "Amadeusz Sławiński" <amadeuszx.slawinski@linux.intel.com>
Cc: Takashi Iwai <tiwai@suse.com>, Jaroslav Kysela <perex@perex.cz>,
	alsa-devel@alsa-project.org,
	Charles Keepax <ckeepax@opensource.cirrus.com>,
	Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
	linux-kernel@vger.kernel.org,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Subject: Re: [PATCH v4 1/3] ALSA: compress: document the compress audio state machine
Date: Mon, 29 Jun 2020 15:04:29 +0530	[thread overview]
Message-ID: <20200629093429.GA2599@vkoul-mobl> (raw)
In-Reply-To: <c29b3199-cebd-2153-5530-e75f76aa8b4b@linux.intel.com>

Hi Amadeusz,

On 29-06-20, 11:05, Amadeusz Sławiński wrote:
> 
> 
> On 6/29/2020 9:50 AM, Vinod Koul wrote:
> > So we had some discussions of the stream states, so I thought it is a
> > good idea to document the state transitions, so add it documentation
> > 
> > Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
> > Signed-off-by: Vinod Koul <vkoul@kernel.org>
> > ---
> >   .../sound/designs/compress-offload.rst        | 51 +++++++++++++++++++
> >   1 file changed, 51 insertions(+)
> > 
> > diff --git a/Documentation/sound/designs/compress-offload.rst b/Documentation/sound/designs/compress-offload.rst
> > index ad4bfbdacc83..b6e9025ae105 100644
> > --- a/Documentation/sound/designs/compress-offload.rst
> > +++ b/Documentation/sound/designs/compress-offload.rst
> > @@ -151,6 +151,57 @@ Modifications include:
> >   - Addition of encoding options when required (derived from OpenMAX IL)
> >   - Addition of rateControlSupported (missing in OpenMAX AL)
> > +State Machine
> > +=============
> > +
> > +The compressed audio stream state machine is described below ::
> > +
> > +                                        +----------+
> > +                                        |          |
> > +                                        |   OPEN   |
> > +                                        |          |
> > +                                        +----------+
> > +                                             |
> > +                                             |
> > +                                             | compr_set_params()
> > +                                             |
> > +                                             v
> > +         compr_free()                   +----------+
> > +  +------------------------------------|          |
> > +  |                                    |   SETUP  |
> > +  |          +------------------------>|          |<-------------------------+
> > +  |          | compr_drain_notify()    +----------+                          |
> > +  |          |         or                   ^                                |
> > +  |          |      compr_stop()            |                                |
> > +  |          |                              | compr_write()                  |
> > +  |          |                              |                                |
> > +  |          |                              |                                |

Not sure, this is not in the version I posted, arrow is from setup ->
prepare. See https://lore.kernel.org/alsa-devel/20200629075002.11436-2-vkoul@kernel.org/

I don't know how it got reversed in your version, maybe the MUA messed
up??

> > +  |          |                         +----------+                          |
> > +  |          |                         |          |   compr_free()           |
> > +  |          |                         |  PREPARE |---------------> A        |
> > +  |          |                         |          |                          |
> > +  |          |                         +----------+                          |
> > +  |          |                              |                                |
> > +  |          |                              |                                |
> > +  |          |                              | compr_start()                  |
> > +  |          |                              |                                |
> > +  |          |                              v                                |
> > +  |    +----------+                    +----------+                          |
> > +  |    |          |    compr_drain()   |          |        compr_stop()      |
> > +  |    |  DRAIN   |<-------------------|  RUNNING |--------------------------+
> > +  |    |          |                    |          |                          |
> > +  |    +----------+                    +----------+                          |
> > +  |                                       |    ^                             |
> > +  |          A                            |    |                             |
> > +  |          |              compr_pause() |    | compr_resume()              |
> > +  |          |                            |    |                             |
> > +  |          v                            v    |                             |
> > +  |    +----------+                   +----------+                           |
> > +  |    |          |                   |          |         compr_stop()      |
> > +  +--->|   FREE   |                   |  PAUSE   |---------------------------+
> > +       |          |                   |          |
> > +       +----------+                   +----------+
> > +
> >   Gapless Playback
> >   ================
> > 
> 
> Line containing compr_free (between SETUP and FREE) seems to be misaligned?

not in the version I posted and see on lore

> If you move prepare to the left and drain in place of drain, it feels like
> you won't need this weird indirection with A

yeah that was a compromise to make it bit neater to me than adding
overlapping arrows...

> Something like:
> 
> >> +                                             v
> > > +         compr_free()                   +----------+
> > > +  +------------------------------------|          |
> > > +  |                                    |   SETUP  |
> > > +  |          +------------------------>|          |<-------------------------+
> > > +  |          | compr_write()           +----------+                          |
> > > +  |          |                              ^                                |
> > > +  |          |                              | compr_drain_notify() or        |
> > > +  |          |                              | compr_stop()                   |
> > > +  |          |                              |                                |
> > > +  |          |                              |                                |
> > > +  |          |                         +----------+                          |
> > > +  |          |                         |          |                          |
> > > +  |          |                         |  DRAIN   |                          |
> > > +  |          |                         |          |                          |
> > > +  |          |                         +----------+                          |
> > > +  |          |                              ^                                |
> > > +  |          |                              |                                |
> > > +  |          |                              | compr_drain()                  |
> > > +  |          |                              |                                |
> > > +  |          |                              |                                |
> > > +  |    +----------+                    +----------+                          |
> > > +  |    |          |    compr_start()   |          |        compr_stop()      |
> > > +  |    |  PREPARE |------------------->|  RUNNING |--------------------------+
> > > +  |    |          |                    |          |                          |
> > > +  |    +----------+                    +----------+                          |
> > > +  |          |                            |    ^                             |
> > > +  |          | compr_free()               |    |                             |
> > > +  |          |              compr_pause() |    | compr_resume()              |
> > > +  |          |                            |    |                             |
> > > +  |          v                            v    |                             |
> > > +  |    +----------+                   +----------+                           |
> > > +  |    |          |                   |          |         compr_stop()      |
> > > +  +--->|   FREE   |                   |  PAUSE   |---------------------------+
> > > +       |          |                   |          |
> > > +       +----------+                   +----------+
> > > +
> 

> but this makes me question PREPARE state, how do you enter it?

a compr_write() moves from SETUP -> PREPARE. Fixing that above looks
better version of mine..

-- 
~Vinod

  reply	other threads:[~2020-06-29 21:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-29  7:49 [PATCH v4 0/3] ALSA: compress: Document stream states and fix gapless SM Vinod Koul
2020-06-29  7:50 ` [PATCH v4 1/3] ALSA: compress: document the compress audio state machine Vinod Koul
2020-06-29  9:05   ` Amadeusz Sławiński
2020-06-29  9:34     ` Vinod Koul [this message]
2020-06-29 10:02       ` Amadeusz Sławiński
2020-06-29 10:59         ` Vinod Koul
2020-06-29  7:50 ` [PATCH v4 2/3] ALSA: compress: document the compress gapless " Vinod Koul
2020-06-29  7:50 ` [PATCH v4 3/3] ALSA: compress: fix partial_drain completion state Vinod Koul

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