Re: [PATCH v13 2/6] media: change au0828 to use Media Device Allocator API

[shuah]

On 3/29/19 2:27 AM, Hans Verkuil wrote:
> On 3/29/19 1:04 AM, Shuah Khan wrote:
> > 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 au0828 to use Media Device Allocator API to allocate media device
> > with the parent usb struct device as the key, so it can be shared with the
> > snd_usb_audio driver.
> >
> > Signed-off-by: Shuah Khan <shuah@xxxxxxxxxx>
> > ---
> >   drivers/media/usb/au0828/Kconfig       |  2 ++
> >   drivers/media/usb/au0828/au0828-core.c | 13 +++++--------
> >   drivers/media/usb/au0828/au0828.h      |  1 +
> >   3 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/media/usb/au0828/Kconfig b/drivers/media/usb/au0828/Kconfig
> > index 65fc067eb864..98de6e24329e 100644
> > --- a/drivers/media/usb/au0828/Kconfig
> > +++ b/drivers/media/usb/au0828/Kconfig
> > @@ -2,6 +2,8 @@
> >   config VIDEO_AU0828
> >   	tristate "Auvitek AU0828 support"
> >   	depends on I2C && INPUT && DVB_CORE && USB && VIDEO_V4L2
> > +	select MEDIA_CONTROLLER
> > +	select MEDIA_CONTROLLER_DVB
>
> Is it required to select MEDIA_CONTROLLER_DVB? Does something fail to work
> if this is unset?

Need this enabled for dvb driver to use media controller. api.

e.g dvb_register_media_device() does all its media controller code
when MEDIA_CONTROLLER_DVB is enabled.

See drivers/media/dvb-core/dvbdev.c

The config still says experimental:

config MEDIA_CONTROLLER_DVB
        bool "Enable Media controller for DVB (EXPERIMENTAL)"
        depends on MEDIA_CONTROLLER && DVB_CORE
        ---help---
          Enable the media controller API support for DVB.

          This is currently experimental.

Is that still accurate? Should be updated?

thanks,
-- Shuah