From 66354f18fe5fbb65f7b10a519654013d6df09f80 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Mon, 1 Apr 2019 20:40:22 -0400 Subject: media: sound/usb: Use Media Controller API to share media resources 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(). Reviewed-by: Takashi Iwai Signed-off-by: Shuah Khan Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- sound/usb/Kconfig | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'sound/usb/Kconfig') diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig index f61b5662bb89..6319b544ba3a 100644 --- a/sound/usb/Kconfig +++ b/sound/usb/Kconfig @@ -15,6 +15,7 @@ config SND_USB_AUDIO select SND_RAWMIDI select SND_PCM select BITREVERSE + select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT=y || MEDIA_SUPPORT=SND_USB_AUDIO) help Say Y here to include support for USB audio and USB MIDI devices. @@ -22,6 +23,9 @@ config SND_USB_AUDIO To compile this driver as a module, choose M here: the module will be called snd-usb-audio. +config SND_USB_AUDIO_USE_MEDIA_CONTROLLER + bool + config SND_USB_UA101 tristate "Edirol UA-101/UA-1000 driver" select SND_PCM -- cgit v1.2.3