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 559B89C3 for ; Mon, 12 May 2014 20:14:55 +0000 (UTC) Received: from mezzanine.sirena.org.uk (mezzanine.sirena.org.uk [106.187.55.193]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E16CA203B8 for ; Mon, 12 May 2014 20:14:53 +0000 (UTC) Date: Mon, 12 May 2014 21:14:38 +0100 From: Mark Brown To: Laurent Pinchart Message-ID: <20140512201438.GE12304@sirena.org.uk> References: <1872038.43ncqEMWSx@avalon> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="TYUwb/23X2F3rAeM" Content-Disposition: inline In-Reply-To: <1872038.43ncqEMWSx@avalon> 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: , --TYUwb/23X2F3rAeM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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=20 > suspend/resume time with camera interfaces for instance, where two comple= tely=20 > unrelated device in the Linux device hierarchy (a camera interface platfo= rm=20 > device in the SoC and an I2C camera sensor) need to be suspended and resu= med=20 > in a controlled order. I'm sure many more use cases exist. > Whether we can (partly) reuse existing infrastructure for this is not cle= ar.=20 > I'd like to gather use cases, to first find out exactly how widespread th= e=20 > need is, and whether we can come up with a common solution or we are real= ly=20 > faced with different classes of similarly looking but distinct issues. This is something ASoC has been resolving since forever with the machine 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. Anyway, I'm definitely interested in this - a couple of the subsystems I maintain are affected and it's something I've thought about a bit. --TYUwb/23X2F3rAeM Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJTcSurAAoJELSic+t+oim9aLcP/RkUOsoMqQmXPA6cqu0x05FL y5on8m3Sz8BhsfJNrqh2zIPHozT3vDTwewbpeWfCiZIvkarY1Z7hcWmMA7inJRFc MQibM/MurSWvhIjQrKEOHI0iwYjvJwgHZYaCU6OhalMukQaM0J9uTpVzzp/4FlBJ FEKx/lrv7c1efNBxX28+6zYiuBaXAQwlHoKT6cGl9m49FOcLqSkNRpqvNTwBcft3 KiqSfoBMgdOPKdp/h8IuRHwYBc+JJN+grDeZLFniZXGMOAmBJ/L/SbviViYQ1Ukg 9OuFVHdoZKG1KhRohl5QFbB+Pb8aQUS9//DoSfho4x92tD2z8BN7/+vB6bg+vip0 ujHybJ9szSeiWjj9Xj51han19Aops0lu2g/x/W4TJ5bKy5enjqywPYLPX6IUoBUc AJFGbdqaTVdRnhdXSeNLuUG20SaS9+o9kc47+9t3LAUzxXPDvRTyP1crc7dk9G4Z pRDcgwWBDhai49zm6XjqB0B+kBAR2VxiycpFXYSe1+4PzZjw2YTnCr3vDee75gA5 D1Z23QtSS5SWMEEqJt1fGnokIfyE8zF5IgKWeJrdzzKKNOEHklZhYfuddujnO5Tr h1D0rmQpKnljnBPn+z6f1YBOUGkGctLFmTXVidC0DmwdTPJOYxBVOCaXOY8YDqoO ODUhK4+twKllIPsmF3zo =T66I -----END PGP SIGNATURE----- --TYUwb/23X2F3rAeM--