[PATCH V3 8/8] ARM: OMAP2+: PMU: Add QoS constraint

Paul Walmsley paul at pwsan.com
Thu Sep 20 13:14:12 EDT 2012


On Mon, 10 Sep 2012, Jon Hunter wrote:

> When CPU-idle is enabled, the MPU sub-system will transition to low power
> states during idle periods. If the PMU is active and the MPU sub-system
> transitions to a low power state, such as retention, then the PMU context
> will be lost and PMU events will stop. To prevent this from happening add a
> QoS constraint whenever PMU is active to prevent the MPU sub-system from
> transitioning to a low power state.
> By default the PMU QoS constraint is set to -1 so it will not prevent any low
> power states and when the PMU is enabled, it is set to 0, so that only C-state
> C0 is allowed. I plan to re-visit this and relax the constraint to allow some
> low power states, but for now I just wish to ensure PMU is working.
> Cc: Ming Lei <ming.lei at canonical.com>
> Cc: Will Deacon <will.deacon at arm.com>
> Cc: Benoit Cousson <b-cousson at ti.com>
> Cc: Paul Walmsley <paul at pwsan.com>
> Cc: Kevin Hilman <khilman at ti.com>
> Signed-off-by: Jon Hunter <jon-hunter at ti.com>

This one looks like 3.7-rc material, due to the dependency on Will's PMU 
runtime PM adaptation series, which is unfortunately not yet in the 
stable merge base that I need to use to send these upstream.  Jon, care to 
update and re-send this one after Linus merges the other PMU patches?

- Paul

More information about the linux-arm-kernel mailing list