On 15 April 2013 21:37, Dirk Brandewie <dirk.brandewie@xxxxxxxxx> wrote:
> If the intel_pstate driver is being used __cpufreq_governor() should NOT be
> called intel_pstate does not implement the target() callback.
>
> Nathan's commit 5800043b2 changed the fence around the call to
> __cpufreq_governor() in __cpufreq_remove_dev() here is the relevant hunk.
No it isn't.
> + if (has_target)
> __cpufreq_governor(data, CPUFREQ_GOV_STOP);
As it has taken care of this limitation.
BUT some of my earlier patches haven't. :(
Here is the fix (Sedat please try this and give your tested-by, use the attached
patch as gmail might break what i am copying in mail)..
Sorry for being late in fixing this issue, i am still down with Tonsil infection
and fever.. Today only i got some power to fix it after seeing Dirk's mail.
Your tested-by may help me to recover quickly :)
@Rafael: I will probably be down for one more week and so not doing any
reviews for now... I do check important mails sent directly to me though.
------------x----------------------x------------------
From: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Mon, 15 Apr 2013 22:43:57 +0530
Subject: [PATCH] cpufreq: Don't call __cpufreq_governor() for drivers without
target()
Some cpufreq drivers implement their own governor and so don't need us to call
generic governors interface via __cpufreq_governor(). Few recent commits haven't
obeyed this law well and we saw some regressions.
This patch tries to fix this issue.
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 3564947..a6f6595 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -858,13 +858,18 @@ static int cpufreq_add_policy_cpu(unsigned int
cpu, unsigned int sibling,
struct device *dev)
{
struct cpufreq_policy *policy;
- int ret = 0;
+ int ret = 0, has_target = 0;
unsigned long flags;
policy = cpufreq_cpu_get(sibling);
WARN_ON(!policy);
- __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
+ rcu_read_lock();
+ has_target = !!rcu_dereference(cpufreq_driver)->target;
+ rcu_read_unlock();
+
+ if (has_target)
+ __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
lock_policy_rwsem_write(sibling);
@@ -877,8 +882,10 @@ static int cpufreq_add_policy_cpu(unsigned int
cpu, unsigned int sibling,
unlock_policy_rwsem_write(sibling);
- __cpufreq_governor(policy, CPUFREQ_GOV_START);
- __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+ if (has_target) {
+ __cpufreq_governor(policy, CPUFREQ_GOV_START);
+ __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+ }
ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
if (ret) {
@@ -1146,7 +1153,8 @@ static int __cpufreq_remove_dev(struct device
*dev, struct subsys_interface *sif
/* If cpu is last user of policy, free policy */
if (cpus == 1) {
- __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
+ if (has_target)
+ __cpufreq_governor(data, CPUFREQ_GOV_POLICY_EXIT);
lock_policy_rwsem_read(cpu);
kobj = &data->kobj;
Attachment:
0001-cpufreq-Don-t-call-__cpufreq_governor-for-drivers-wi.patch
Description: Binary data
