Messages in this thread | | | Date | Tue, 20 Oct 2015 10:40:03 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [GIT PULL] On-demand device probing |
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On Tue, 20 Oct 2015, Rob Herring wrote:
> > The probe ordering is not the entire picture, though. > > > > Even if you get the probe ordering right, the problem is going to show up in > > multiple other places: system suspend/resume, runtime PM, system shutdown, > > unbinding of drivers. In all of those cases it is necessary to handle things > > in a specific order if there is a dependency. > > My understanding was with deferred probe that it also solves suspend > ordering problems because things are suspended in reverse order of > probing.
Devices are suspended in reverse order of _registration_. Not of probing.
Furthermore, that applies only to devices that use synchronous suspend. Async suspend is becoming common, and there the only restrictions are parent-child relations plus whatever explicit requirements that drivers impose by calling device_pm_wait_for_dev().
Alan Stern
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