From mboxrd@z Thu Jan  1 00:00:00 1970
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [RFD] Functional dependencies between devices
Date: Thu, 7 Jan 2016 13:29:24 -0800
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To: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Linux PM list <linux-pm@vger.kernel.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Alan Stern <stern@rowland.harvard.edu>, Grant Likely <grant.likely@linaro.org>, Mark Brown <broonie@kernel.og>, Rob Herring <robh@kernel.org>, Thierry Reding <treding@nvidia.com>, Dmitry Torokhov <dtor@google.com>, Geert Uytterhoeven <geert@linux-m68k.org>, Michael Turquette <mturquette@baylibre.com>

On Thu, Jan 07, 2016 at 03:55:43PM +0100, Tomeu Vizoso wrote:
> On 30 October 2015 at 23:52, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Tue, Oct 27, 2015 at 04:24:14PM +0100, Rafael J. Wysocki wrote:
> >> My idea is to represent a supplier-consumer dependency between devices (or
> >> more precisely between device+driver combos) as a "link" object containing
> >> pointers to the devices in question, a list node for each of them and some
> >> additional information related to the management of those objects, ie.
> >> something like:
> >>
> >> struct device_link {
> >>       struct device *supplier;
> >>       struct list_head supplier_node;
> >>       struct device *consumer;
> >>       struct list_head consumer_node;
> >>       <flags, status etc>
> >> };
> >>
> >> In general, there will be two lists of those things per device, one list
> >> of links to consumers and one list of links to suppliers.
> >>
> >> In that picture, links will be created by calling, say:
> >>
> >> int device_add_link(struct device *me, struct device *my_supplier, unsigned int flags);
> >
> > At first glance, I like this, nice.  Now to see how well it can be
> > implemented :)
> 
> Hi Greg,
> 
> what's your opinion on using this to order device probes so we don't
> try to probe a device that we know it has unfulfilled dependencies?

Why would that matter, unless you can prove it's faster, I wouldn't
bother.

greg k-h