From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTP id 9AAEC6FC for ; Mon, 12 May 2014 20:27:20 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [95.142.166.194]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 2A8892039A for ; Mon, 12 May 2014 20:27:20 +0000 (UTC) From: Laurent Pinchart To: Mark Brown Date: Mon, 12 May 2014 22:27:14 +0200 Message-ID: <1890814.sS5FutD9xo@avalon> In-Reply-To: <20140512201438.GE12304@sirena.org.uk> References: <1872038.43ncqEMWSx@avalon> <20140512201438.GE12304@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart107708403.DWJZrKsOhC"; micalg="pgp-sha1"; protocol="application/pgp-signature" Cc: ksummit-discuss@lists.linuxfoundation.org Subject: Re: [Ksummit-discuss] [TECH TOPIC] PM dependencies List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --nextPart107708403.DWJZrKsOhC Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="us-ascii" Hi Mark, On Monday 12 May 2014 21:14:38 Mark Brown wrote: > On Mon, May 12, 2014 at 07:43:22PM +0200, Laurent Pinchart wrote: > > The problem is not limited to IOMMUs. We have similar dependencies = at > > suspend/resume time with camera interfaces for instance, where two > > completely unrelated device in the Linux device hierarchy (a camera= > > interface platform device in the SoC and an I2C camera sensor) need= to be > > suspended and resumed in a controlled order. I'm sure many more use= cases > > exist. > >=20 > > Whether we can (partly) reuse existing infrastructure for this is n= ot > > clear. I'd like to gather use cases, to first find out exactly how > > widespread the need is, and whether we can come up with a common so= lution > > or we are really faced with different classes of similarly looking = but > > distinct issues. > > This is something ASoC has been resolving since forever with the mach= ine > drivers, Russell King recently created a generic version of the code > that does the dependency deferral glue (see linux/component.h). It's= > not a model of elegance but it ends up getting the job done. That solves the probe time dependencies, but unfortunately not the runt= ime PM=20 dependencies. > Anyway, I'm definitely interested in this - a couple of the subsystem= s I > maintain are affected and it's something I've thought about a bit. =2D-=20 Regards, Laurent Pinchart --nextPart107708403.DWJZrKsOhC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. Content-Transfer-Encoding: 7Bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQEcBAABAgAGBQJTcS6nAAoJEIkPb2GL7hl1ftsH/RRUwZwwen7gP7y/WgchW324 wRO3XzBr1xbfponyvypMZEhM3vsbCjQMu9bFGrs8VMOGb3egiz/YRVAA4iLp4HD0 CzDW5v3MX4rfceLfsVf2Nei1r/fVkTRZoJZ5gO9kY1JF4UakCLoCZdAjN+A3eFL/ /C8nfve7KGrX6Ww1uE4X+0EyAL7PsyMU2KOzgJYUQeNbaxXTnoLX47s0X5r7ZhT4 AJZ+bMWmLjkrPA0QX7yE3maQDxNVSREeXq/QBdt7mXKsxrk1A9W1INFps57JWXe/ b8DaoV2XHKXuB2RhYZZgRyoM7HpPtGRxoLHTaI36nfA944dnVIaeqDzLrD/2VjA= =V/27 -----END PGP SIGNATURE----- --nextPart107708403.DWJZrKsOhC--