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

[Lars-Peter Clausen]

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.