From: Takashi Iwai <tiwai@suse.de>
To: shuah@kernel.org
Cc: mchehab@kernel.org, perex@perex.cz, tiwai@suse.com,
hverkuil@xs4all.nl, alsa-devel@alsa-project.org,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
Subject: Re: [alsa-devel] [PATCH v9 4/4] sound/usb: Use Media Controller API to share media resources
Date: Wed, 19 Dec 2018 14:51:33 +0100 [thread overview]
Message-ID: <s5hefadbp5m.wl-tiwai@suse.de> (raw)
In-Reply-To: <2fb40852e4035b2a58010ce7416448918f12804f.1545154778.git.shuah@kernel.org>
On Tue, 18 Dec 2018 18:59:39 +0100,
shuah@kernel.org wrote:
>
> From: Shuah Khan <shuah@kernel.org>
>
> 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@kernel.org>
Feel free to take my ack regarding the sound stuff:
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Thanks!
Takashi
next prev parent reply other threads:[~2018-12-19 13:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-18 17:59 [PATCH v9 0/4] Media Device Allocator API shuah
2018-12-18 17:59 ` [PATCH v9 1/4] media: " shuah
2018-12-18 17:59 ` [PATCH v9 2/4] media: change au0828 to use " shuah
2018-12-18 17:59 ` [PATCH v9 3/4] media: media.h: Enable ALSA MEDIA_INTF_T* interface types shuah
2018-12-18 17:59 ` [PATCH v9 4/4] sound/usb: Use Media Controller API to share media resources shuah
2018-12-19 13:51 ` Takashi Iwai [this message]
2019-01-11 14:57 ` [alsa-devel] " shuah
2019-01-11 14:59 ` Hans Verkuil
2019-01-11 15:04 ` shuah
2019-01-18 8:36 ` Hans Verkuil
2019-01-18 21:54 ` shuah
2019-01-19 1:03 ` shuah
2019-01-19 10:30 ` Hans Verkuil
2019-01-20 19:32 ` shuah
2019-01-21 14:46 ` [PATCH v9 0/4] Media Device Allocator API Hans Verkuil
2019-01-24 1:35 ` shuah
2019-01-24 7:30 ` Hans Verkuil
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