Re: mx31 snd and mc13783 codec status

[Sascha Hauer <s.hauer@pengutronix.de>]

On Thu, Apr 01, 2010 at 06:01:38PM +0200, Valentin Longchamp wrote:
> Hi Sascha,
>
> Sascha Hauer wrote:
>>
>> Find the latest version of my code here:
>>
>> The following changes since commit 01e77706cdde7c0b47e5ca1f4284a795504c7c40:
>>   Linus Torvalds (1):
>>         Merge branch 'for-linus' of git://gitorious.org/linux-omap-dss2/linux
>>
>> are available in the git repository at:
>>
>>   git://git.pengutronix.de/git/sha/linux-2.6.git mc13783
>>
>> Sascha Hauer (3):
>>       add a mc13783 codec driver
>>       add phycore-mc13783 sound support
>>       pcm038: add sound support
>>
>>  arch/arm/mach-mx2/mach-pcm038.c |   23 ++-
>>  sound/soc/codecs/Kconfig        |    4 +
>>  sound/soc/codecs/Makefile       |    2 +
>>  sound/soc/codecs/mc13783.c      |  727 +++++++++++++++++++++++++++++++++++++++
>>  sound/soc/codecs/mc13783.h      |   32 ++
>>  sound/soc/imx/Kconfig           |    9 +
>>  sound/soc/imx/Makefile          |    3 +
>>  sound/soc/imx/phycore-mc13783.c |  160 +++++++++
>>  8 files changed, 959 insertions(+), 1 deletions(-)
>>  create mode 100644 sound/soc/codecs/mc13783.c
>>  create mode 100644 sound/soc/codecs/mc13783.h
>>  create mode 100644 sound/soc/imx/phycore-mc13783.c
>>
>>> And do you know if your initial mc13783 codec support coupled with   
>>> mx31 had some limitations ? Our setup is quite straightforward, we 
>>> have  direct connection from the mx31 to the mc13783 on a single SSI.
>>
>> Our board uses both SSI channels of the MC13783 which we then mux into
>> one channel in the DAM unit. I don't know how this affects you.
>>
>
> I have struggled with the DAM unit (this thing is an awful bulk of  
> wires) and now I get some sound on the loudspeaker.
>
> The thing is that I get a less than a second sound loop (I use aplay to  
> test, so userspace app should be ok), as if the buffer that the fiq asm  
> interrupt (from ssi_fiq.S) copies to the SSI hardware never was updated.
>
> If I have understood the fiq behaviour correctly, you have a asm fiq  
> interrupt that does copy a larger tx buffer into the SSI hardware.  
> Besides it, you have the imx_ssi_timer_callback that checks when the tx  
> buffer was completely copied. If it is the case, then a new buffer tx  
> buffer is "issued" with the snd_pcm_period_elapsed call (and then  
> snd_pcm_update_hw_ptr0). Is this behaviour correct ?

Yes.

>
> If then it looks like on my system, I have a problem with the  
> snd_pcm_update_hw_ptr0 call.

You could try reverting b4e82b5b785670b68136765059d1afc65c0ae023. Though
I have tested it on my boards it may have some implications.

Sascha


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