From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 130C7C67838 for ; Sun, 9 Dec 2018 11:37:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D3FB220865 for ; Sun, 9 Dec 2018 11:37:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3FB220865 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-media-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726214AbeLILhR (ORCPT ); Sun, 9 Dec 2018 06:37:17 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:55535 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726184AbeLILhR (ORCPT ); Sun, 9 Dec 2018 06:37:17 -0500 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 916F480809; Sun, 9 Dec 2018 12:37:11 +0100 (CET) Date: Sun, 9 Dec 2018 12:37:14 +0100 From: Pavel Machek To: Mauro Carvalho Chehab Cc: shuah , perex@perex.cz, tiwai@suse.com, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org Subject: Re: [RFC PATCH v8 1/4] media: Media Device Allocator API Message-ID: <20181209113714.GA21784@amd> References: <20181119085931.GA28607@amd> <73c22137-9c7a-75c8-8cd1-3736c63c2d40@kernel.org> <20181209080944.GA7561@amd> <20181209092715.50a7e4e4@coco.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="gKMricLos+KVdGMg" Content-Disposition: inline In-Reply-To: <20181209092715.50a7e4e4@coco.lan> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org --gKMricLos+KVdGMg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > On Thu 2018-12-06 08:33:14, shuah wrote: > > > On 11/19/18 1:59 AM, Pavel Machek wrote: =20 > > > >On Thu 2018-11-01 18:31:30, shuah@kernel.org wrote: =20 > > > >>From: Shuah Khan > > > >> > > > >>Media Device Allocator API to allows multiple drivers share a media= device. > > > >>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 whe= n all > > > >>the references are released. =20 > > > > > > > >Sounds like a ... bad idea? > > > > > > > >That's what new "media control" framework is for, no? > > > > > > > >Why do you need this? =20 > > >=20 > > > Media control framework doesn't address this problem of ownership of = the > > > media device when non-media drivers have to own the pipeline. In this= case, > > > snd-usb owns the audio pipeline when an audio application is using the > > > device. Without this work, media drivers won't be able to tell if snd= -usb is > > > using the tuner and owns the media pipeline. > > >=20 > > > I am going to clarify this in the commit log. =20 > >=20 > > I guess I'll need the explanation, yes. > >=20 > > How can usb soundcard use the tuner? I thought we'd always have > > userspace component active and moving data between tuner and usb sound > > card? >=20 > It sounds that the description of the patch is not 100%, as it seems > that you're not seeing the hole picture. >=20 > This is designed to solve a very common usecase for media devices > where one physical device (an USB stick) provides both audio > and video. Aha, ok, it makes sense now. Thanks! Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --gKMricLos+KVdGMg Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlwM/moACgkQMOfwapXb+vKOCACcCSevIvvLj57RR7yYVXHr54DH emcAoK0Pb/5LFFQjUm/27hJjWMsRwkXQ =XydS -----END PGP SIGNATURE----- --gKMricLos+KVdGMg--