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Subject[PATCH] PM / OPP: discard duplicate OPP additions
Date
From: Chander Kashyap <k.chander@samsung.com>

It may be possible to unregister and re-register the cpufreq driver.
One such example is arm big-little IKS cpufreq driver. While
re-registering the driver, same OPPs may get added again.

This patch detects the duplicacy and discards them.

Signed-off-by: Chander Kashyap <k.chander@samsung.com>
Signed-off-by: Inderpal Singh <inderpal.s@samsung.com>
---
drivers/base/power/opp.c | 28 +++++++++++++++++++---------
1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 2553867..2e803a9 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -443,23 +443,33 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
new_opp->u_volt = u_volt;
new_opp->available = true;

- /* Insert new OPP in order of increasing frequency */
+ /*
+ * Insert new OPP in order of increasing frequency
+ * and discard if already present
+ */
head = &dev_opp->opp_list;
list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
- if (new_opp->rate < opp->rate)
+ if (new_opp->rate <= opp->rate)
break;
else
head = &opp->node;
}

- list_add_rcu(&new_opp->node, head);
- mutex_unlock(&dev_opp_list_lock);
+ if (new_opp->rate != opp->rate) {
+ list_add_rcu(&new_opp->node, head);
+ mutex_unlock(&dev_opp_list_lock);
+
+ /*
+ * Notify the changes in the availability of the operable
+ * frequency/voltage list.
+ */
+ srcu_notifier_call_chain(&dev_opp->head,
+ OPP_EVENT_ADD, new_opp);
+ } else {
+ mutex_unlock(&dev_opp_list_lock);
+ kfree(new_opp);
+ }

- /*
- * Notify the changes in the availability of the operable
- * frequency/voltage list.
- */
- srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ADD, new_opp);
return 0;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_add);
--
1.7.9.5


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