Messages in this thread | | | Date | Sat, 10 Sep 2011 11:23:02 +0530 | From | Santosh <> | Subject | Re: [PATCH v2 0/5] CPU PM notifiers |
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On Friday 09 September 2011 11:30 PM, Kevin Hilman wrote: > Santosh Shilimkar<santosh.shilimkar@ti.com> writes: > > [...] > >> This patch set tries to address concerns with platform pm code >> calling into the driver for every block in the Cortex A9s >> during idle, hotplug, and suspend. The first patch adds cpu pm >> notifiers that can be called by platform code, the second uses >> the notifier to save and restore the GIC state, and the third >> saves the VFP state. >> >> The notifiers are used for two types of events, CPU PM events and >> CPU cluster PM events. CPU PM events are used to save and restore >> per-cpu context when a single CPU is preparing to enter or has >> just exited a low power state. For example, the VFP saves the >> last thread context, and the GIC saves banked CPU registers. >> >> CPU cluster events are used after all the CPUs in a power domain >> have been prepared for the low power state. The GIC uses these >> events to save global register state. > > Stepping back from my earlier objections, I think I had a fundamental > misunderstanding about what these notifiers should be used for. > > The current assumptions/goals seem to be > > 1) used only for devices in the same power domain as the CPU (cluster) > 2) use only for one specific power state of the CPU (cluster): off. > > For awhile now, we've been discussing how to better coordinate CPU PM > transitions (CPUidle) with non-CPU PM transitions (runtime PM) for > devices that are tightly coupled to the CPU, but not necessarily in the > same powerdomain. > > I was assuming (and hoping) that CPU PM notifiers could be used to do > that, but the more I think about it, I don't think we can achieve the > current CPU PM goals and the coordination with runtime PM with this > series. > > I think it's more likely that we'll need to do some work with Rafael's > new PM domains to make that work correctly. > > So, I'll retract my objections to this series, and feel free to add > > Reviewed-by: Kevin Hilman<khilman@ti.com> > Will add. Thanks for the review Kevin.
Regards Santosh
Regards
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