[alsa-devel] [PATCH] ALSA: usb-audio: Add quirk for MOTU MicroBook II

[Takashi Iwai]

On Thu, 28 Feb 2019 20:34:04 +0100,
Manuel Reinhardt wrote:
> 
> Add an entry to the quirks-table to for usb-audio to recognize the
> Microbook II (although it only exposes vendor interfaces). A simple boot
> quirk is also implemented to set up the sample rate and  make sure that
> no audio urbs are sent before the device is ready.
> 
> This patch only provides audio playback and capture at 96kHz sample
> rate. Notice the following shortcomings:
> 
> - The sample rate is currently hardcoded to 96k although the device also
>   supports 48k and 44.1k.
> 
> - The various mixer controls of the MicroBook are not made available.
> 
> - The keep-iface control should be on by default because the device
>   shuts down whenever the altsetting is reset which is usually unwanted.
>   (I don't know the best way to do this)
> 
> - The communication format used by the MicroBook for sample rate setting
>   and also other setup has been reverse engineered by looking at the
>   usbmon output while running the windows driver through virtualbox. In
>   this patch the first byte of every message is set to \0 while in the
>   observed communications the first byte acts as a "message-counter"
>   increasing its value with every message sent. Leaving it at \0 does
>   not seem to affect the device.
> 
> Signed-off-by: Manuel Reinhardt <manuel.rhdt at gmail.com>

Applied, thanks.


Takashi