From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: Multiple parents in device driver model and Common Display Framework (CDF) Date: Tue, 12 Feb 2013 14:29:55 -0800 Message-ID: <20130212222955.GA25968@kroah.com> References: <511A5A15.4000306@stericsson.com> <20130212220209.GA23856@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mail-pa0-f54.google.com (mail-pa0-f54.google.com [209.85.220.54]) by gabe.freedesktop.org (Postfix) with ESMTP id 15661E5C6C for ; Tue, 12 Feb 2013 14:29:58 -0800 (PST) Received: by mail-pa0-f54.google.com with SMTP id fa10so355071pad.27 for ; Tue, 12 Feb 2013 14:29:57 -0800 (PST) Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Marcus Lorentzon Cc: arnd@arndb.de, Daniel Vetter , dri-devel@lists.freedesktop.org, Tomi Valkeinen , Laurent Pinchart List-Id: dri-devel@lists.freedesktop.org On Tue, Feb 12, 2013 at 11:20:04PM +0100, Marcus Lorentzon wrote: > Den 12 feb 2013 23:02 skrev "Greg KH" : > > > > On Tue, Feb 12, 2013 at 04:04:53PM +0100, Marcus Lorentzon wrote: > > > 3) Daniel V hinted that multiple parents (or multiple busses) is > > > something that has been discussed as a limitation of device driver > > > model before. And that maybe now was the time to fix that or at > > > least sort out how to handle it. > > > > No, it's the other way around, we have discussed ways about having > > multiple drivers control a single device at the same time. =A0The > > "multiple parents" issue has come up a number of times with the power > > management people, but they solved this by keeping a separate tree of > > how to properly control and walk things to handle power domains and the > > like. > > > Thanks, > does this mean there are no other devices in the kernel that sit on multi= ple > busses that can be use as inspiration? Lots of devices do this, but they all have an individual 'struct device' for the part that sits on each bus, with a single driver controlling both of them > Was the discussion about handling one device from multiple drivers conclu= ded/ > implemented? It sounds very much what we are trying to do? Or this was ju= st > some f2f discussion? We've been talking about it off and on for many years now, and I think the framework in the driver core is almost there, but in reality, the different "types" of devices usually solve this problem, so we've never spent the time to do anything else here. sorry, greg k-h