Re: [PATCH 1/1] PM / Runtime: let rpm_resume fail if rpm disabled and device suspended.

[Kevin Hilman <khilman@linaro.org>]

Alan Stern <stern@rowland.harvard.edu> writes:

[...]

> What we really need to figure out is how to tell the PM core which
> devices may safely have their runtime callbacks invoked during system
> suspend.  For those devices, the core can avoid calling
> pm_runtime_disable() during the suspend_late phase.  That would address
> your requirements, right?

Yes, and something I've attempted a few times over the years, most
recently during the introduction of the pm_runtime_force* functions[1],
which I thought was again an attempt to work around this issue.

I don't think Rafael has ever been too thrilled with that idea
(including the last time[2]), but I think we're to a point now that we
have to manage this somehow.

My attempt to let the bus/subsystem/pm_domain set a flag might be
too simplistic, but I do agree we do need som way to tell the PM core
that runtime PM callbacks are (still) safe.

Kevin

[1] http://marc.info/?l=linux-pm&m=139343222014989&w=2
[2] http://marc.info/?l=linux-pm&m=139346327619875&w=2