* question on snd_soc_dai_link_event
@ 2012-10-26 11:58 Sebastien LEDUC
2012-10-26 17:01 ` Mark Brown
0 siblings, 1 reply; 6+ messages in thread
From: Sebastien LEDUC @ 2012-10-26 11:58 UTC (permalink / raw)
To: alsa-devel
Cc: Mark Brown (broonie@opensource.wolfsonmicro.com),
Liam Girdwood (lrg@ti.com)
Hi,
I have one question about current implementation of function snd_soc_dai_link_event
Currently, on power up, it calls hw_params on the source and sink dai drivers, and digital_mute(0) on the sink dai driver
I wonder why it does not call the full hw_params / prepare / trigger sequence on both dai drivers to start the 2 DAIs.
Thanks in advance
Regards,
Sebastien
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: question on snd_soc_dai_link_event
2012-10-26 11:58 question on snd_soc_dai_link_event Sebastien LEDUC
@ 2012-10-26 17:01 ` Mark Brown
2012-11-21 17:56 ` Sebastien LEDUC
2013-01-18 14:07 ` Sebastien LEDUC
0 siblings, 2 replies; 6+ messages in thread
From: Mark Brown @ 2012-10-26 17:01 UTC (permalink / raw)
To: Sebastien LEDUC; +Cc: alsa-devel, Liam Girdwood (lrg@ti.com)
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On Fri, Oct 26, 2012 at 01:58:54PM +0200, Sebastien LEDUC wrote:
Fix your mailer to word wrap within paragraphs, it makes your mails hard
to read if you don't do this. I've reflowed for legibility.
> I wonder why it does not call the full hw_params / prepare / trigger
> sequence on both dai drivers to start the 2 DAIs.
None of the drivers that use this actually have any of those calls so I
didn't bother. Especially in the case of trigger it's unlikely that an
off-SoC device without DMA would need this, though of course it could
happen.
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: question on snd_soc_dai_link_event
2012-10-26 17:01 ` Mark Brown
@ 2012-11-21 17:56 ` Sebastien LEDUC
2012-11-22 0:32 ` Mark Brown
2013-01-18 14:07 ` Sebastien LEDUC
1 sibling, 1 reply; 6+ messages in thread
From: Sebastien LEDUC @ 2012-11-21 17:56 UTC (permalink / raw)
To: Mark Brown; +Cc: alsa-devel, Liam Girdwood (lrg@ti.com)
Hi Mark
One further question on the dai_link widget mechanism.
Currently the code in soc_probe_link_dais, the code will call snd_soc_dapm_new_pcm
to create the dai_link widget and the routes.
For a capture stream, it creates the following routes:
Cpu_dai widget -> dai_link widget -> codec_dai widget
And for a playback stream:
Codec_dai widget -> dai_link widget -> cpu_dai widget
Shouldn't it be the opposite directions in both cases?
Or did I miss something?
Thanks
Regards
Sebastien
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: question on snd_soc_dai_link_event
2012-11-21 17:56 ` Sebastien LEDUC
@ 2012-11-22 0:32 ` Mark Brown
0 siblings, 0 replies; 6+ messages in thread
From: Mark Brown @ 2012-11-22 0:32 UTC (permalink / raw)
To: Sebastien LEDUC; +Cc: alsa-devel, Liam Girdwood (lrg@ti.com)
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On Wed, Nov 21, 2012 at 06:56:55PM +0100, Sebastien LEDUC wrote:
> For a capture stream, it creates the following routes:
> Cpu_dai widget -> dai_link widget -> codec_dai widget
> And for a playback stream:
> Codec_dai widget -> dai_link widget -> cpu_dai widget
Remember that for a CODEC<->CODEC link both devices will be CODECs so
their widgets have the opposite sense as everything is named in a CPU
centric fashion. The important thing is that we link playback to
capture and capture to playback.
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: question on snd_soc_dai_link_event
2012-10-26 17:01 ` Mark Brown
2012-11-21 17:56 ` Sebastien LEDUC
@ 2013-01-18 14:07 ` Sebastien LEDUC
2013-01-21 4:31 ` Mark Brown
1 sibling, 1 reply; 6+ messages in thread
From: Sebastien LEDUC @ 2013-01-18 14:07 UTC (permalink / raw)
To: Mark Brown; +Cc: alsa-devel, liam.r.girdwood
Hi Mark,
Coming back on this topic:
We are trying to use the codec <-> codec approach to model our
on-SoC DSP.
So in our case it would be quite important that the full sequence
of ops is called, so that we are not dependent on which ops the codec
we use is relying on.
I am even thinking that it could be worth creating an internal PCM
for the dai link that has the params field, and to call the standard
soc functions (soc_pcm_open, ...) on it from the dai_link widget DAPM
callback to start / stop the PCM.
Any feedback?
Thanks
Regards
Sebastien
> -----Original Message-----
> From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com]
> Sent: Friday, October 26, 2012 7:02 PM
> To: Sebastien LEDUC
> Cc: alsa-devel@alsa-project.org; Liam Girdwood (lrg@ti.com)
> Subject: Re: question on snd_soc_dai_link_event
>
> On Fri, Oct 26, 2012 at 01:58:54PM +0200, Sebastien LEDUC wrote:
>
> Fix your mailer to word wrap within paragraphs, it makes your mails hard
> to read if you don't do this. I've reflowed for legibility.
>
> > I wonder why it does not call the full hw_params / prepare / trigger
> > sequence on both dai drivers to start the 2 DAIs.
>
> None of the drivers that use this actually have any of those calls so I
> didn't bother. Especially in the case of trigger it's unlikely that an
> off-SoC device without DMA would need this, though of course it could
> happen.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: question on snd_soc_dai_link_event
2013-01-18 14:07 ` Sebastien LEDUC
@ 2013-01-21 4:31 ` Mark Brown
0 siblings, 0 replies; 6+ messages in thread
From: Mark Brown @ 2013-01-21 4:31 UTC (permalink / raw)
To: Sebastien LEDUC; +Cc: alsa-devel, liam.r.girdwood
On Fri, Jan 18, 2013 at 03:07:29PM +0100, Sebastien LEDUC wrote:
Once again, don't top post.
> I am even thinking that it could be worth creating an internal PCM
> for the dai link that has the params field, and to call the standard
> soc functions (soc_pcm_open, ...) on it from the dai_link widget DAPM
> callback to start / stop the PCM.
> Any feedback?
I think what's important here is that any resulting code looks sane and
works well; I'm not sure that going all the way up the stack is going to
help with that as you're more likely to expose assumptions about the
calling environment but I've not paid it much concrete attention.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-01-21 4:37 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-10-26 11:58 question on snd_soc_dai_link_event Sebastien LEDUC
2012-10-26 17:01 ` Mark Brown
2012-11-21 17:56 ` Sebastien LEDUC
2012-11-22 0:32 ` Mark Brown
2013-01-18 14:07 ` Sebastien LEDUC
2013-01-21 4:31 ` Mark Brown
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