[alsa-devel] fsl_ssi.c: Getting channel slips with fsl_ssi.c in TDM (network) mode.

Roberto Fichera kernel at tekno-soft.it
Thu Oct 29 09:04:48 CET 2015


On 10/28/2015 11:09 PM, Caleb Crome wrote:
> On Wed, Oct 28, 2015 at 6:59 AM, Caleb Crome <caleb at crome.org> wrote:
>> On Wed, Oct 28, 2015 at 1:11 AM, Roberto Fichera <kernel at tekno-soft.it> wrote:
>>> On 10/27/2015 07:57 PM, Fabio Estevam wrote:
>>>> [Adding Roberto in the thread as he is also trying to get SSI TDM support/
>>> Thanks Fabio,
>>>
>>> I'm also having the same issue but employing SSI in TDM master mode against a SLIC Si32178
>>> using its PCM mode. PCLK is at 2048KHz, FSYNC is 8KHz slot length is 32 bits (SSI wants
>>> this since when in master mode) but valid data set to be 8bits in the SSI register.
>>>
>>> My Current situation is that I've a custom fsl_ssi.c driver to control the SSI in TDM master mode
>>> both PCLK and FSYNC works perfectly fine, the SLIC has a register that I can check via SPI for
>>> such purpose, I can see the clocking status from its side. The main problem I've is exactly the same
>>> Caleb is having, after a certain amount of SDMA transfers, roughly 1000 or so, everything stops
>>> without any apparent reason.
>> My problem is that the channels randomly slip a slot and all words end
>> up in the wrong slot.  I suspect this is a DMA issue, but I really
>> haven't diagnosed it yet.  I don't get a full stop on the data.
>>
>> FYI, I'm using a very recent 4.3 kernel from linus's repo, but 4.2
>> behaved the same.
>>
> Now I'm recalling when I tried the patches on 4.1, everything
> definitely froze.  What kernel are you using?.  I'm basically using
> the 4.3-rc7

Currently the Freescale offical v3.14.28_ga_1.0.0 coming with Yocto Fido.

>
> -Caleb
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