[alsa-devel] [PATCH v4 2/5] ASoC: Move standard kcontrol helpers to the component level

[Lars-Peter Clausen]

On 05/10/2014 10:31 AM, Shawn Guo wrote:
> On Sat, May 10, 2014 at 09:11:04AM +0200, Lars-Peter Clausen wrote:
>> On 05/10/2014 09:04 AM, Lars-Peter Clausen wrote:
>> [..]
>>>> The error message only shows up with Debian wheezy and does not with
>>>> yocto rootfs.  And even when the error message shows, the audio still
>>>> functions well on Debian wheezy.  So it's just a noisy error message
>>>> for me which is only seen after your kernel patch.
>>>
>>> The keyword here is "seen". The error quite likely predated the commit, but
>>> it was silently discarded.
>>>
>>> regmap_read() returns -EBUSY when there is no cached register value and
>>> cache_only is set to true. But I'm not sure why that would happen, try to
>>> add some printks to _regmap_read() to see if this is the source and if it is
>>> why it is.
>>
>> Both SGTL5000_CHIP_ANA_ADC_CTRL and SGTL5000_CHIP_MIC_CTRL don't
>> have an entry in sgtl5000_reg_defaults. So if cache_only is true,
>> controls which use these registers will return -EBUSY when you try
>> to read or write them.
>
> Hmm, it's a wm8962 than sgtl5000 on board imx6q-sabresd.

Ok, misread the boardname. But the issue will be the same. cache_only = true 
and trying to read/update a register that is not in the cache.