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[1/4] opp: add dev_pm_opp_is_turbo() helper

Message ID 20150729102435.GB9584@linux
State New
Headers show

Commit Message

Viresh Kumar July 29, 2015, 10:24 a.m. UTC 
On 28-07-15, 16:27, Pavel Machek wrote:
> Typo.
> 
> And this is not exactly most helpful comment. opp is turbo... returns
> if opp was turbo. Explanation what "turbo" means in this context would
> be nice. I'm pretty sure it is not about air compression :-).

Does this make it any better:

Comments

Viresh Kumar July 29, 2015, 10:56 a.m. UTC | #1 
On 29-07-15, 12:53, Pavel Machek wrote:
> So any combination of normal OPPs can be sustained for arbitrary time
> within the temperature range?

Maybe not. That's why we user thermal framework to sense such
situations and react accordingly.

> And as soon as any turbo OPP is enabled, we produce more heat than
> TDP?

But yeah, this will cross all limits. Shall generate more heat or may
consume lots of power for very small benefit in performance. And so
very short duration bursts of this are used by very few platforms.
diff mbox

Patch

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index e039cf024a6c..da8ec7f824d5 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -281,9 +281,13 @@  unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
 
 /**
- * dev_pm_opp_is_turbo() - Returns true if opp was trubo OPP
+ * dev_pm_opp_is_turbo() - Returns if opp is turbo OPP or not
  * @opp: opp for which turbo mode is being verified
  *
+ * Turbo OPPs are not for normal use, and can be enabled (under certain
+ * conditions) for short duration of times to finish high throughput work
+ * quickly. Running on them for longer times may overheat the chip.
+ *
  * Return: true if opp is turbo opp, else false.
  *
  * Locking: This function must be called under rcu_read_lock(). opp is a rcu