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

[Jean Pihet]

Paul, Kevin,

On Mon, Dec 19, 2011 at 10:02 PM, Paul Walmsley <paul at pwsan.com> 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:
>
>> From: Jean Pihet <j-pihet at ti.com>
>>
>> . 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