On Sat, Feb 4, 2012 at 4:06 PM, Turquette, Mike [off-list ref] wrote:

On Sat, Feb 4, 2012 at 11:02 AM, Colin Cross [off-list ref] wrote:

quoted

On Tue, Jan 31, 2012 at 7:00 PM, Robert Lee [off-list ref] wrote:

quoted

Make necessary changes to add implement time keepign and irq enabling

keeping

quoted

in the core cpuidle code. ?This will allow the remove of these
functionalities from the platform cpuidle implementations.

Signed-off-by: Robert Lee <redacted>
---
?drivers/cpuidle/cpuidle.c | ? 75 +++++++++++++++++++++++++++++++++++---------
?include/linux/cpuidle.h ? | ? 26 ++++++++++-----
?2 files changed, 76 insertions(+), 25 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 59f4261..8ea0fc3 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c

@@ -57,14 +57,18 @@ static int __cpuidle_register_device(struct cpuidle_device *dev);

?* cpuidle_idle_call - the main idle loop
?*
?* NOTE: no locks or semaphores should be used here
+ * NOTE: Should only be called from a local irq disabled context
?* return non-zero on failure
+ *
?*/
?int cpuidle_idle_call(void)
?{
? ? ? ?struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
? ? ? ?struct cpuidle_driver *drv = cpuidle_get_driver();
? ? ? ?struct cpuidle_state *target_state;
- ? ? ? int next_state, entered_state;
+ ? ? ? int idx, ret = 0;
+ ? ? ? ktime_t t1, t2;
+ ? ? ? s64 diff;

? ? ? ?if (off)
? ? ? ? ? ? ? ?return -ENODEV;

@@ -86,37 +90,76 @@ int cpuidle_idle_call(void)

?#endif

? ? ? ?/* ask the governor for the next state */
- ? ? ? next_state = cpuidle_curr_governor->select(drv, dev);
+ ? ? ? idx = cpuidle_curr_governor->select(drv, dev);
+
+ ? ? ? target_state = &drv->states[idx];
+
+ ? ? ? /*
+ ? ? ? ?* Check with the device to see if it can enter this state or if another
+ ? ? ? ?* state should be used.
+ ? ? ? ?*/
+ ? ? ? if (target_state->pre_enter) {
+ ? ? ? ? ? ? ? idx = target_state->
+ ? ? ? ? ? ? ? ? ? ? ? pre_enter(dev, drv, idx);

Unnecessary line wrap and braces.

What's the point of the pre_enter call? ?This seems very similar to
the prepare call that was removed in 3.2. ?Drivers can already demote

Hi Colin,

I asked Rob to re-introduce the .prepare callback (not .pre_enter).

The short version of why I requested this is so that I can experiment
with modifying wake-up latency and theshold values dynamically based
on PM QoS constraints. ?For an OMAP-specific example, I'd like to see
our C-states no longer model both MPU and CORE power domains, and
instead only model the MPU. ?Then when entering idle the PM QoS
constraints against the CORE power domain's wake-up latency can be
considered in the .prepare callback which will affect the C-state
parameters as well as program the CORE low power target state.

.pre_enter isn't really right for the above case so I'm happy for it
to be dropped, but I'll probably re-introduce something like .prepare
in the future...

Hey Mike, yes, this pre_enter has it's own purpose that appears
separate from the reasoning for the prepare function you mention here.
 Perhaps it would be best to re-add the prepare function and make use
of it in the OMAP code all in one patch series so that it doesn't get
removed again due to apparent lack of use in the upstream kernel.  I'm
sure we'll discuss it further this week in person.

Regards,
Mike

quoted

the target state in their enter call. ?The only thing you do between
pre_enter and enter is trace and account for the time. ?Is there some
long call you don't want included in the idle time? ?Some
documentation would help, and you need to very clearly define the
semantics of when post_enter gets called when pre_enter or enter
return errors.

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