Re: [alsa-devel] [PATCH v9 4/4] sound/usb: Use Media Controller API to share media resources

[shuah]

On 12/19/18 6:51 AM, Takashi Iwai wrote:
> On Tue, 18 Dec 2018 18:59:39 +0100,
> shuah@xxxxxxxxxx wrote:
> > From: Shuah Khan <shuah@xxxxxxxxxx>
> >
> > Media Device Allocator API to allows multiple drivers share a media device.
> > This API solves a very common use-case for media devices where one physical
> > device (an USB stick) provides both audio and video. When such media device
> > exposes a standard USB Audio class, a proprietary Video class, two or more
> > independent drivers will share a single physical USB bridge. In such cases,
> > it is necessary to coordinate access to the shared resource.
> >
> > Using this API, drivers can allocate a media device with the shared struct
> > device as the key. Once the media device is allocated by a driver, other
> > drivers can get a reference to it. The media device is released when all
> > the references are released.
> >
> > Change the ALSA driver to use the Media Controller API to share media
> > resources with DVB, and V4L2 drivers on a AU0828 media device.
> >
> > The Media Controller specific initialization is done after sound card is
> > registered. ALSA creates Media interface and entity function graph nodes
> > for Control, Mixer, PCM Playback, and PCM Capture devices.
> >
> > snd_usb_hw_params() will call Media Controller enable source handler
> > interface to request the media resource. If resource request is granted,
> > it will release it from snd_usb_hw_free(). If resource is busy, -EBUSY is
> > returned.
> >
> > Media specific cleanup is done in usb_audio_disconnect().
> >
> > Signed-off-by: Shuah Khan <shuah@xxxxxxxxxx>
>
> Feel free to take my ack regarding the sound stuff:
>    Reviewed-by: Takashi Iwai <tiwai@xxxxxxx>
>
>
> Thanks!
>
> Takashi

Hi Mauro,

Any update on this patch series?

thanks,
-- Shuah