[PATCH v6 0/6] PM QoS: implement the OMAP low level constraints management code

Paul, Kevin,

On Mon, Dec 19, 2011 at 10:02 PM, Paul Walmsley [off-list ref] wrote:

Hi Jean

I'm really sorry it's taken me so long to do detailed review of these
patches for merging... anyway -

On Wed, 14 Dec 2011, jean.pihet at newoldbits.com wrote:

quoted

From: Jean Pihet <redacted>

. Implement the devices wake-up latency constraints using the global
? device PM QoS notification handler which applies the constraints to the
? underlying layer
. Implement the low level code which controls the power domains next power
? states, through the hwmod and pwrdm layers
. Add cpuidle and power domains wake-up latency figures for OMAP3, cf.
? comments in the code and [1] for the details on where the numbers
? are magically coming from
. Implement the relation between the cpuidle and per-device PM QoS frameworks
? in the OMAP3 specific idle callbacks.
? The chosen C-state shall satisfy the following conditions:
? ?. the 'valid' field is enabled,
? ?. it satisfies the enable_off_mode flag,
? ?. the next state for MPU and CORE power domains is not lower than the
? ? ?state programmed by the per-device PM QoS.

I've been reviewing these closely. ?It looks to me that are some issues
that need to be resolved before all of them are mergeable.

One issue that I noticed in this series is that there are some locking
issues in patch 1. ?It looks to me that calls to
_pwrdm_wakeuplat_update_pwrst() can race with each other, since it's
called outside the lock?

I fixed this by moving the lock so that it includes the update of the
next power state.

Speaking of the locking, currently a spinlock is used and it could be
replaced by a more efficient mutex. This is ok at the condition that
this code is not called from interrupt context?

Kevin,
Do you know if the per-device constraint code can be called from
interrupt context?

...

- Paul

Jean