Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Wed, 8 Jun 2016 22:48:23 +0200 | Subject | Re: [RFC][PATCH 2/5] driver core: Functional dependencies tracking support |
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On Wed, Jun 8, 2016 at 8:35 PM, Mark Brown <broonie@kernel.org> wrote: > On Wed, Jun 08, 2016 at 08:12:34PM +0200, Rafael J. Wysocki wrote: >> On Wed, Jun 8, 2016 at 2:48 PM, Mark Brown <broonie@kernel.org> wrote: >> > On Thu, Jan 14, 2016 at 02:54:17AM +0100, Rafael J. Wysocki wrote: > >> >> + * A side effect of the link creation is re-ordering of dpm_list and the >> >> + * devices_kset list by moving the consumer device and all devices depending >> >> + * on it to the ends of those lists. > >> > How does this work in the scenario where a device instantiates a child >> > device then uses services that child provides to complete the >> > initializiation? We do have that scenario currently for on chip >> > regulators to allow external regulators to be used. > >> I'm not sure I understand the question correctly, but it that is the >> parent and a child, we don't need an extra link entity to represent >> that dependency, as parent-child dependencies are taken by the current >> code into account already. > > A parent (especially a MFD) may create a child to fulfil a role that > could also be filled by a non-parent device, if that happens then > depending on what ends up creating these links (it's not 100% clear from > this series) it's likely that the link creation will also end up > registering a dependency unless we do something special. Now I think > about it this does depend on how we create the children though, it's > less likely to be an issue if the dependencies are created by firmware > code.
If that's a non-child device, I would expect it to exist beforehand and then the link creation would only enforce the specific ordering of certain operations (like runtime PM or async suspend/resume) between the two devices linked by it. That shouldn't be problematic in principle.
Let me redo the series, though (that may take a couple of days realistically).
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