Messages in this thread | | | From | Kevin Hilman <> | Subject | Re: [linux-pm] [PATCH 0/3] coupled cpuidle state support | Date | Wed, 14 Mar 2012 07:23:59 -0700 |
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Colin Cross <ccross@android.com> writes:
> On Tue, Mar 13, 2012 at 5:28 PM, Colin Cross <ccross@android.com> wrote: >> On Tue, Mar 13, 2012 at 4:52 PM, Kevin Hilman <khilman@ti.com> wrote:
[...]
>>> >>> Checking the ready_count seemed like an easy way to do this, but did you >>> have any other mechanisms in mind for CPUs to communicate that they've >>> exited/aborted? >> >> Why not set a flag from CPU1 when it exits the low power state, and >> have CPU0 spin on the powerdomain register or the flag? You can then >> use the parallel barrier function to ensure both cpus have seen the >> flag and reset it to 0 before returning. > > I realized the parallel barrier helper was not included in the patch > set I posted, it will be in the next patch set.
Do you have an ETA for the next patchset? I'll be glad to give it a spin on OMAP4.
> Short version, no caller to cpuidle_coupled_parallel_barrier will > return before all cpus in the coupled set have called it. It allows > you to resynchronize the cpus after an abort to ensure they have all > seen the abort flag before clearing it and returning, leaving > everything in the correct state for the next idle attempt.
OK, this sounds like it will work well for what I need.
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