[alsa-devel] Mic detection on Mackbook Pro 12,1 (CS4208)

[Takashi Iwai]

On Thu, 10 Nov 2016 22:52:52 +0100,
Paulo Fidalgo wrote:
> 
> Hi,
> 
> After reporting the issue on bugzilla
> (https://bugzilla.kernel.org/show_bug.cgi?id=155601) I felt I could do
> more in order to try to get a patch to fix the issue.
> 
> Basically when I plug an headset(mic+headphone), it only detects the
> headphone not the mic.
> 
> Since I assumed the "memory address" of the 0x18 pin is wrong, I've
> tried to change some values in order to get it working.

The value you're referring to isn't a "memory address" at all.
It's a "pin configuration" value, containing the information like
the location, purpose, sequence number of the given pin, and it's
encoded in 32bit integer.  Basically it's merely a hint for drivers to
configure the system properly.

Refer to the HD-audio specification document for more details.


Takashi