[alsa-devel] Ordering in soc_pcm_hw_params()

[jonsmirl at gmail.com]

On Tue, Aug 12, 2014 at 7:45 AM, jonsmirl at gmail.com <jonsmirl at gmail.com> wrote:
> On Tue, Aug 12, 2014 at 4:42 AM, Lars-Peter Clausen <lars at metafoo.de> wrote:
>> On 08/11/2014 03:35 PM, jonsmirl at gmail.com wrote:
>>>
>>> soc_pcm_hw_params() sets the parameters in this order:
>>> link, codec, cpu, platform
>>>
>>> This is tripping me up when switching between the 44100 and 48000
>>> families.  If previous song was 44100 then the codec has sysclk set to
>>> the 44100 family.
>>>
>>> Now I play a 48000 family song. codec gets new hardware params and
>>> errors out because sysclk is still in the 44100 family.
>>>
>>> I have code in the cpu set_hw_params which will switch the sysclk, but
>>> it never gets to run because the codec set_hw_params() has already
>>> errored out.
>>>
>>> Shouldn't this order be:
>>> platform, link, cpu, codec
>>
>>
>> What I don't understand is why does the CPU DAI driver change the sysclk for
>> the CODEC DAI driver? What I'd expect is that the machine driver sets the
>> sysclk for both the CODEC and the CPU DAI. In this case everything should
>> work fine.
>
> The machine driver is simple-card. It is not smart enough to change
> the sysclk between 22.5Mhz and 24.5Mhz depending on what music is
> being played.

Having said that, should we make simple-card smart enough to do that?


>
>
>>
>> - Lars
>>
>
>
>
> --
> Jon Smirl
> jonsmirl at gmail.com



-- 
Jon Smirl
jonsmirl at gmail.com