[alsa-devel] ASoC: rt5640, rt5651 jack-detect and BYT SST suspend/resume patches / status update

[Pierre-Louis Bossart]

>>> Carlo or Pierre-Louis can one of you check using e.g.
>>> the left + right speaker test in gnome-control-panel's
>>> sound config-applet if that left only goes to the left
>>> speaker and right only goes to the right speaker?
>>>
>>> My bytcr-rt5651 tablet has only one speaker, but I
>>> here sound for both the left and right speaker tests
>>> which suggests some right-to-left mixing is happening
>>> which we don't want on devices with stereo speakers.
>>> Could be there is some mixing happening outside of the
>>> codec on this tablet, still it would be good to test
>>> this.
>>
>> Just tested this and it works fine on my hardware.
> 
> Great, thank you.
> 
> Note I've seem the same magic mono mixing happening on a
> CHT + rt5651 tablet I've also been testing on. It is weird
> how the hardware seems to magically mix the left and
> right channels to the mono speaker without explicitly
> enabling that in the codec/mixer settings as one needs
> to do for the rt5640 and rt5645. But hey if it works
> it works :)

The rt5651 does not have a built-in amplifier, it provides a line out 
that is then fed into a discrete amplifier, the mixing could happen at 
that level too.
We use the rt5651 for validation with a line-out -> line-in loopback and 
there is no issue with implicit mixing with the UCM files I pushed on my 
github (evolved from Carlo's rework).