On 09/17/2014 04:20 PM, Shilimkar, Santosh wrote:
Sorry for the format. Emailing from webmail.
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[ ... ]
+static int omap_enter_idle_smp(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ struct idle_statedata *cx = state_ptr + index;
+ unsigned long flag;
+
+ raw_spin_lock_irqsave(&mpu_lock, flag);
Why do you need this spin_lock_irqsave ? Aren't the local irqs already
disabled ?
[Santosh] Actually at one point of time before the idle consolidation the local
irq disable was inside the idle drivers. Now with that moved to core layer,
I think plain spin_lock/unlock() should work.
ok.
+ cx->mpu_state_vote++;
+ if (cx->mpu_state_vote == num_online_cpus()) {
+ pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
+ omap_set_pwrdm_state(mpu_pd, cx->mpu_state);
+ }
+ raw_spin_unlock_irqrestore(&mpu_lock, flag);
+
+ omap4_enter_lowpower(dev->cpu, cx->cpu_state);
+
+ raw_spin_lock_irqsave(&mpu_lock, flag);
+ if (cx->mpu_state_vote == num_online_cpus())
+ omap_set_pwrdm_state(mpu_pd, PWRDM_POWER_ON);
+ cx->mpu_state_vote--;
+ raw_spin_unlock_irqrestore(&mpu_lock, flag);
I am not sure that will work. What happens if a cpu exits idle and then
re-enter idle immediately ?
[Santosh] It works and that case is already taken care. CPU exist the idle and
then votes
out for cluster state and if it reenters with the right targeted state, the
cluster state would
be picked.
It isn't possible to have one cpu disabling the coherency, while the
other one is looking for a lock ? Or eg. cpu0 is on WFI then cpu1 is the
last entering idle. While cpu1 is entering 'lowpower', cpu0 exits the
wfi check the state vote and set the power domain on. In the meantime
cpu1 disables the coherency and cpu0 decrease the vote and release the
lock. Could be possible there is a very small racy window here ?
Could you try a long run of this little program:
https://git.linaro.org/power/pm-qa.git/blob/HEAD:/cpuidle/cpuidle_killer.c
[Santosh] I am sure there will not be any issue with the long run test case
here.
Lets see if Nishant sees anything otherwise
Ok. Make sure the cpu is effectively entering your C2 state with the
sleep duration in the test program.
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