[alsa-devel] [PATCH v3 1/2] ALSA: usb-audio: UAC2 jack detection

[Takashi Iwai]

On Sat, 24 Mar 2018 03:25:23 +0100,
Andrew Chant wrote:
> 
> This implements UAC2 jack detection support, presenting
> jack status as a boolean read-only mono mixer.
> 
> The presence of any channel in the UAC2_TE_CONNECTOR
> control for a terminal will result in the mixer saying
> the jack is connected.
> 
> Mixer naming follows the convention in sound/core/ctljack.c,
> terminating the mixer with " Jack".
> For additional clues as to which jack is being presented,
> the name is prefixed with " - Input Jack" or " - Output Jack"
> depending on if it's an input or output terminal.
> 
> This is required because terminal names are ambiguous
> between inputs and outputs and often duplicated -
> Bidirectional terminal types (0x400 -> 0x4FF)
> "... may be used separately for input only or output only.
> These types require two Terminal descriptors. Both have the same type."
> (quote from "USB Device Class Definition for Terminal Types")
> 
> Since bidirectional terminal types are common for headphone adapters,
> this distinguishes between two otherwise identically-named
> jack controls.
> 
> Tested with a UAC2 audio device with connector control capability.
> 
> Signed-off-by: Andrew Chant <achant at google.com>

Applied now, thanks.


Takashi