[PATCH V3 1/2] cpufreq: Make sure CPU is running on a freq from freq-table

[PATCH V3 1/2] cpufreq: Make sure CPU is running on a freq from freq-table

[Viresh Kumar]

Sometimes boot loaders set CPU frequency to a value outside of frequency table
present with cpufreq core. In such cases CPU might be unstable if it has to run
on that frequency for long duration of time and so its better to set it to a
frequency which is specified in freq-table. This also makes cpufreq stats
inconsistent as cpufreq-stats would fail to register because current frequency
of CPU isn't found in freq-table.

Because we don't want this change to effect boot process badly, we go for the
next freq which is >= policy->cur ('cur' must be set by now, otherwise we will
end up setting freq to lowest of the table as 'cur' is initialized to zero).

In case current frequency doesn't match any frequency from freq-table, we throw
warnings to user, so that user can get this fixed in their bootloaders or
freq-tables.

On some systems we can't really say what frequency we're running at the moment
and so for these we have added another flag: CPUFREQ_SKIP_INITIAL_FREQ_CHECK.

Reported-by: Carlos Hernandez <ceh@ti.com>
Reported-and-tested-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V2->V3:
- Minor cleanups suggested by Rafael
- New patch: 2/2 (cpufreq: Mark x86 drivers with CPUFREQ_SKIP_INITIAL_FREQ_CHECK
  flag)
- Rebased on PM/bleeding-edge

 drivers/cpufreq/cpufreq.c    | 40 ++++++++++++++++++++++++++++++++++++++++
 drivers/cpufreq/freq_table.c | 22 ++++++++++++++++++++++
 include/linux/cpufreq.h      | 11 +++++++++++
 3 files changed, 73 insertions(+)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 606224a..f13320a 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1042,6 +1042,46 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
 		}
 	}
 
+	/*
+	 * Sometimes boot loaders set CPU frequency to a value outside of
+	 * frequency table present with cpufreq core. In such cases CPU might be
+	 * unstable if it has to run on that frequency for long duration of time
+	 * and so its better to set it to a frequency which is specified in
+	 * freq-table. This also makes cpufreq stats inconsistent as
+	 * cpufreq-stats would fail to register because current frequency of CPU
+	 * isn't found in freq-table.
+	 *
+	 * Because we don't want this change to effect boot process badly, we go
+	 * for the next freq which is >= policy->cur ('cur' must be set by now,
+	 * otherwise we will end up setting freq to lowest of the table as 'cur'
+	 * is initialized to zero).
+	 *
+	 * We are passing target-freq as "policy->cur - 1" otherwise
+	 * __cpufreq_driver_target() would simply fail, as policy->cur will be
+	 * equal to target-freq.
+	 */
+	if (!(cpufreq_driver->flags & CPUFREQ_SKIP_INITIAL_FREQ_CHECK)
+	    && has_target()) {
+		/* Are we running at unknown frequency ? */
+		ret = cpufreq_frequency_table_get_index(policy, policy->cur);
+		if (ret == -EINVAL) {
+			/* Warn user and fix it */
+			pr_warn("%s: CPU%d: Running at unlisted freq: %u KHz\n",
+				__func__, policy->cpu, policy->cur);
+			ret = __cpufreq_driver_target(policy, policy->cur - 1,
+				CPUFREQ_RELATION_L);
+
+			/*
+			 * Reaching here after boot in a few seconds may not
+			 * mean that system will remain stable at "unknown"
+			 * frequency for longer duration. Hence, a BUG_ON().
+			 */
+			BUG_ON(ret);
+			pr_warn("%s: CPU%d: Unlisted initial frequency changed to: %u KHz\n",
+				__func__, policy->cpu, policy->cur);
+		}
+	}
+
 	/* related cpus should atleast have policy->cpus */
 	cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
 
diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
index 3458d27..a8ac042 100644
--- a/drivers/cpufreq/freq_table.c
+++ b/drivers/cpufreq/freq_table.c
@@ -178,7 +178,29 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 }
 EXPORT_SYMBOL_GPL(cpufreq_frequency_table_target);
 
+int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
+		unsigned int freq)
+{
+	struct cpufreq_frequency_table *table;
+	int i;
+
+	table = cpufreq_frequency_get_table(policy->cpu);
+	if (unlikely(!table)) {
+		pr_debug("%s: Unable to find frequency table\n", __func__);
+		return -ENOENT;
+	}
+
+	for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+		if (table[i].frequency == freq)
+			return i;
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(cpufreq_frequency_table_get_index);
+
 static DEFINE_PER_CPU(struct cpufreq_frequency_table *, cpufreq_show_table);
+
 /**
  * show_available_freqs - show available frequencies for the specified CPU
  */
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index ee5fe9d..03174ab 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -252,6 +252,15 @@ struct cpufreq_driver {
  */
 #define CPUFREQ_ASYNC_NOTIFICATION  (1 << 4)
 
+/*
+ * Set by drivers which don't want cpufreq core to check if CPU is running at a
+ * frequency present in freq-table exposed by the driver. For other drivers if
+ * CPU is found running at an out of table freq, we will try to set it to a freq
+ * from the table. And if that fails, we will stop further boot process by
+ * issuing a BUG_ON().
+ */
+#define CPUFREQ_SKIP_INITIAL_FREQ_CHECK	(1 << 5)
+
 int cpufreq_register_driver(struct cpufreq_driver *driver_data);
 int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);
 
@@ -447,6 +456,8 @@ int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
 				   unsigned int target_freq,
 				   unsigned int relation,
 				   unsigned int *index);
+int cpufreq_frequency_table_get_index(struct cpufreq_policy *policy,
+		unsigned int freq);
 
 void cpufreq_frequency_table_update_policy_cpu(struct cpufreq_policy *policy);
 ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf);
-- 
1.7.12.rc2.18.g61b472e

[PATCH V3 2/2] cpufreq: Mark x86 drivers with CPUFREQ_SKIP_INITIAL_FREQ_CHECK flag

[Viresh Kumar]

On some systems we can't really say what frequency we're running at the moment
and so for these we shouldn't check if we are running at a frequency present in
frequency table. For now mark all x86 drivers with this flag:
CPUFREQ_SKIP_INITIAL_FREQ_CHECK.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Rafael,

Please check if I have missed any driver or added an extra one.

 drivers/cpufreq/acpi-cpufreq.c       | 1 +
 drivers/cpufreq/cpufreq-nforce2.c    | 1 +
 drivers/cpufreq/e_powersaver.c       | 1 +
 drivers/cpufreq/elanfreq.c           | 1 +
 drivers/cpufreq/gx-suspmod.c         | 1 +
 drivers/cpufreq/ia64-acpi-cpufreq.c  | 1 +
 drivers/cpufreq/intel_pstate.c       | 2 +-
 drivers/cpufreq/longhaul.c           | 1 +
 drivers/cpufreq/longrun.c            | 2 +-
 drivers/cpufreq/p4-clockmod.c        | 1 +
 drivers/cpufreq/pcc-cpufreq.c        | 2 +-
 drivers/cpufreq/powernow-k6.c        | 1 +
 drivers/cpufreq/powernow-k7.c        | 1 +
 drivers/cpufreq/powernow-k8.c        | 3 ++-
 drivers/cpufreq/sc520_freq.c         | 1 +
 drivers/cpufreq/speedstep-centrino.c | 1 +
 drivers/cpufreq/speedstep-ich.c      | 1 +
 drivers/cpufreq/speedstep-smi.c      | 1 +
 18 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index caf41eb..b8e4f79 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -903,6 +903,7 @@ static struct freq_attr *acpi_cpufreq_attr[] = {
 };
 
 static struct cpufreq_driver acpi_cpufreq_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= acpi_cpufreq_target,
 	.bios_limit	= acpi_processor_get_bios_limit,
diff --git a/drivers/cpufreq/cpufreq-nforce2.c b/drivers/cpufreq/cpufreq-nforce2.c
index a05b876..b3222f6 100644
--- a/drivers/cpufreq/cpufreq-nforce2.c
+++ b/drivers/cpufreq/cpufreq-nforce2.c
@@ -370,6 +370,7 @@ static int nforce2_cpu_exit(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver nforce2_driver = {
+	.flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.name = "nforce2",
 	.verify = nforce2_verify,
 	.target = nforce2_target,
diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c
index 9012b8b..0826bda 100644
--- a/drivers/cpufreq/e_powersaver.c
+++ b/drivers/cpufreq/e_powersaver.c
@@ -389,6 +389,7 @@ static int eps_cpu_exit(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver eps_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= eps_target,
 	.init		= eps_cpu_init,
diff --git a/drivers/cpufreq/elanfreq.c b/drivers/cpufreq/elanfreq.c
index de08acf..426d14d 100644
--- a/drivers/cpufreq/elanfreq.c
+++ b/drivers/cpufreq/elanfreq.c
@@ -194,6 +194,7 @@ __setup("elanfreq=", elanfreq_setup);
 
 
 static struct cpufreq_driver elanfreq_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.get		= elanfreq_get_cpu_frequency,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= elanfreq_target,
diff --git a/drivers/cpufreq/gx-suspmod.c b/drivers/cpufreq/gx-suspmod.c
index d83e826..7bfad48 100644
--- a/drivers/cpufreq/gx-suspmod.c
+++ b/drivers/cpufreq/gx-suspmod.c
@@ -438,6 +438,7 @@ static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
  *   MediaGX/Geode GX initialize cpufreq driver
  */
 static struct cpufreq_driver gx_suspmod_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.get		= gx_get_cpuspeed,
 	.verify		= cpufreq_gx_verify,
 	.target		= cpufreq_gx_target,
diff --git a/drivers/cpufreq/ia64-acpi-cpufreq.c b/drivers/cpufreq/ia64-acpi-cpufreq.c
index 53c6ac6..907bf9a 100644
--- a/drivers/cpufreq/ia64-acpi-cpufreq.c
+++ b/drivers/cpufreq/ia64-acpi-cpufreq.c
@@ -344,6 +344,7 @@ acpi_cpufreq_cpu_exit (
 
 
 static struct cpufreq_driver acpi_cpufreq_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify 	= cpufreq_generic_frequency_table_verify,
 	.target_index	= acpi_cpufreq_target,
 	.get 		= acpi_cpufreq_get,
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 5f1cbae..6c8f5d3 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -725,7 +725,7 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver intel_pstate_driver = {
-	.flags		= CPUFREQ_CONST_LOOPS,
+	.flags		= CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= intel_pstate_verify_policy,
 	.setpolicy	= intel_pstate_set_policy,
 	.get		= intel_pstate_get,
diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
index 45bafdd..16c0a37 100644
--- a/drivers/cpufreq/longhaul.c
+++ b/drivers/cpufreq/longhaul.c
@@ -909,6 +909,7 @@ static int longhaul_cpu_init(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver longhaul_driver = {
+	.flags	= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.target_index = longhaul_target,
 	.get	= longhaul_get,
diff --git a/drivers/cpufreq/longrun.c b/drivers/cpufreq/longrun.c
index 074971b..b67d341 100644
--- a/drivers/cpufreq/longrun.c
+++ b/drivers/cpufreq/longrun.c
@@ -278,7 +278,7 @@ static int longrun_cpu_init(struct cpufreq_policy *policy)
 
 
 static struct cpufreq_driver longrun_driver = {
-	.flags		= CPUFREQ_CONST_LOOPS,
+	.flags		= CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= longrun_verify_policy,
 	.setpolicy	= longrun_set_policy,
 	.get		= longrun_get,
diff --git a/drivers/cpufreq/p4-clockmod.c b/drivers/cpufreq/p4-clockmod.c
index 3d1cba9..92b7e2b 100644
--- a/drivers/cpufreq/p4-clockmod.c
+++ b/drivers/cpufreq/p4-clockmod.c
@@ -234,6 +234,7 @@ static unsigned int cpufreq_p4_get(unsigned int cpu)
 }
 
 static struct cpufreq_driver p4clockmod_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= cpufreq_p4_target,
 	.init		= cpufreq_p4_cpu_init,
diff --git a/drivers/cpufreq/pcc-cpufreq.c b/drivers/cpufreq/pcc-cpufreq.c
index e2b4f40..eafe4ca 100644
--- a/drivers/cpufreq/pcc-cpufreq.c
+++ b/drivers/cpufreq/pcc-cpufreq.c
@@ -571,7 +571,7 @@ static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver pcc_cpufreq_driver = {
-	.flags = CPUFREQ_CONST_LOOPS,
+	.flags = CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.get = pcc_get_freq,
 	.verify = pcc_cpufreq_verify,
 	.target = pcc_cpufreq_target,
diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c
index 643e795..fe60021 100644
--- a/drivers/cpufreq/powernow-k6.c
+++ b/drivers/cpufreq/powernow-k6.c
@@ -150,6 +150,7 @@ static unsigned int powernow_k6_get(unsigned int cpu)
 }
 
 static struct cpufreq_driver powernow_k6_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= powernow_k6_target,
 	.init		= powernow_k6_cpu_init,
diff --git a/drivers/cpufreq/powernow-k7.c b/drivers/cpufreq/powernow-k7.c
index 946708a..4e67abc 100644
--- a/drivers/cpufreq/powernow-k7.c
+++ b/drivers/cpufreq/powernow-k7.c
@@ -679,6 +679,7 @@ static int powernow_cpu_exit(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver powernow_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= powernow_target,
 	.get		= powernow_get,
diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
index 0023c7d..ffe89ba 100644
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1204,7 +1204,8 @@ out:
 }
 
 static struct cpufreq_driver cpufreq_amd64_driver = {
-	.flags		= CPUFREQ_ASYNC_NOTIFICATION,
+	.flags		= CPUFREQ_ASYNC_NOTIFICATION |
+				CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= powernowk8_target,
 	.bios_limit	= acpi_processor_get_bios_limit,
diff --git a/drivers/cpufreq/sc520_freq.c b/drivers/cpufreq/sc520_freq.c
index 6adb354..d6a1cf6 100644
--- a/drivers/cpufreq/sc520_freq.c
+++ b/drivers/cpufreq/sc520_freq.c
@@ -89,6 +89,7 @@ static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
 
 
 static struct cpufreq_driver sc520_freq_driver = {
+	.flags	= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.get	= sc520_freq_get_cpu_frequency,
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.target_index = sc520_freq_target,
diff --git a/drivers/cpufreq/speedstep-centrino.c b/drivers/cpufreq/speedstep-centrino.c
index 4e1daca..887fd43 100644
--- a/drivers/cpufreq/speedstep-centrino.c
+++ b/drivers/cpufreq/speedstep-centrino.c
@@ -505,6 +505,7 @@ out:
 }
 
 static struct cpufreq_driver centrino_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.name		= "centrino", /* should be speedstep-centrino,
 					 but there's a 16 char limit */
 	.init		= centrino_cpu_init,
diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
index 7639b2b..67596e7 100644
--- a/drivers/cpufreq/speedstep-ich.c
+++ b/drivers/cpufreq/speedstep-ich.c
@@ -307,6 +307,7 @@ static int speedstep_cpu_init(struct cpufreq_policy *policy)
 
 
 static struct cpufreq_driver speedstep_driver = {
+	.flags	= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.name	= "speedstep-ich",
 	.verify	= cpufreq_generic_frequency_table_verify,
 	.target_index = speedstep_target,
diff --git a/drivers/cpufreq/speedstep-smi.c b/drivers/cpufreq/speedstep-smi.c
index 0f5326d..4f23289 100644
--- a/drivers/cpufreq/speedstep-smi.c
+++ b/drivers/cpufreq/speedstep-smi.c
@@ -308,6 +308,7 @@ static int speedstep_resume(struct cpufreq_policy *policy)
 }
 
 static struct cpufreq_driver speedstep_driver = {
+	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
 	.name		= "speedstep-smi",
 	.verify		= cpufreq_generic_frequency_table_verify,
 	.target_index	= speedstep_target,
-- 
1.7.12.rc2.18.g61b472e

Re: [PATCH V3 2/2] cpufreq: Mark x86 drivers with CPUFREQ_SKIP_INITIAL_FREQ_CHECK flag

[Rafael J. Wysocki]

On Friday, November 29, 2013 09:45:27 AM Viresh Kumar wrote:
> On some systems we can't really say what frequency we're running at the moment
> and so for these we shouldn't check if we are running at a frequency present in
> frequency table. For now mark all x86 drivers with this flag:
> CPUFREQ_SKIP_INITIAL_FREQ_CHECK.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> Rafael,
> 
> Please check if I have missed any driver or added an extra one.

I think you haven't missed any of them.

That said, you need to do this in patch [1/2], or the kernel between
patches [1/2] and [2/2] may be broken on some systems.

If you want to do that in separate patches, the current [2/2] should be
[1/2] and vice versa.

I guess they will apply in the reverse order?

>  drivers/cpufreq/acpi-cpufreq.c       | 1 +
>  drivers/cpufreq/cpufreq-nforce2.c    | 1 +
>  drivers/cpufreq/e_powersaver.c       | 1 +
>  drivers/cpufreq/elanfreq.c           | 1 +
>  drivers/cpufreq/gx-suspmod.c         | 1 +
>  drivers/cpufreq/ia64-acpi-cpufreq.c  | 1 +
>  drivers/cpufreq/intel_pstate.c       | 2 +-
>  drivers/cpufreq/longhaul.c           | 1 +
>  drivers/cpufreq/longrun.c            | 2 +-
>  drivers/cpufreq/p4-clockmod.c        | 1 +
>  drivers/cpufreq/pcc-cpufreq.c        | 2 +-
>  drivers/cpufreq/powernow-k6.c        | 1 +
>  drivers/cpufreq/powernow-k7.c        | 1 +
>  drivers/cpufreq/powernow-k8.c        | 3 ++-
>  drivers/cpufreq/sc520_freq.c         | 1 +
>  drivers/cpufreq/speedstep-centrino.c | 1 +
>  drivers/cpufreq/speedstep-ich.c      | 1 +
>  drivers/cpufreq/speedstep-smi.c      | 1 +
>  18 files changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index caf41eb..b8e4f79 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -903,6 +903,7 @@ static struct freq_attr *acpi_cpufreq_attr[] = {
>  };
>  
>  static struct cpufreq_driver acpi_cpufreq_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= acpi_cpufreq_target,
>  	.bios_limit	= acpi_processor_get_bios_limit,
> diff --git a/drivers/cpufreq/cpufreq-nforce2.c b/drivers/cpufreq/cpufreq-nforce2.c
> index a05b876..b3222f6 100644
> --- a/drivers/cpufreq/cpufreq-nforce2.c
> +++ b/drivers/cpufreq/cpufreq-nforce2.c
> @@ -370,6 +370,7 @@ static int nforce2_cpu_exit(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver nforce2_driver = {
> +	.flags = CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.name = "nforce2",
>  	.verify = nforce2_verify,
>  	.target = nforce2_target,
> diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c
> index 9012b8b..0826bda 100644
> --- a/drivers/cpufreq/e_powersaver.c
> +++ b/drivers/cpufreq/e_powersaver.c
> @@ -389,6 +389,7 @@ static int eps_cpu_exit(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver eps_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= eps_target,
>  	.init		= eps_cpu_init,
> diff --git a/drivers/cpufreq/elanfreq.c b/drivers/cpufreq/elanfreq.c
> index de08acf..426d14d 100644
> --- a/drivers/cpufreq/elanfreq.c
> +++ b/drivers/cpufreq/elanfreq.c
> @@ -194,6 +194,7 @@ __setup("elanfreq=", elanfreq_setup);
>  
>  
>  static struct cpufreq_driver elanfreq_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.get		= elanfreq_get_cpu_frequency,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= elanfreq_target,
> diff --git a/drivers/cpufreq/gx-suspmod.c b/drivers/cpufreq/gx-suspmod.c
> index d83e826..7bfad48 100644
> --- a/drivers/cpufreq/gx-suspmod.c
> +++ b/drivers/cpufreq/gx-suspmod.c
> @@ -438,6 +438,7 @@ static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
>   *   MediaGX/Geode GX initialize cpufreq driver
>   */
>  static struct cpufreq_driver gx_suspmod_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.get		= gx_get_cpuspeed,
>  	.verify		= cpufreq_gx_verify,
>  	.target		= cpufreq_gx_target,
> diff --git a/drivers/cpufreq/ia64-acpi-cpufreq.c b/drivers/cpufreq/ia64-acpi-cpufreq.c
> index 53c6ac6..907bf9a 100644
> --- a/drivers/cpufreq/ia64-acpi-cpufreq.c
> +++ b/drivers/cpufreq/ia64-acpi-cpufreq.c
> @@ -344,6 +344,7 @@ acpi_cpufreq_cpu_exit (
>  
>  
>  static struct cpufreq_driver acpi_cpufreq_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify 	= cpufreq_generic_frequency_table_verify,
>  	.target_index	= acpi_cpufreq_target,
>  	.get 		= acpi_cpufreq_get,
> diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> index 5f1cbae..6c8f5d3 100644
> --- a/drivers/cpufreq/intel_pstate.c
> +++ b/drivers/cpufreq/intel_pstate.c
> @@ -725,7 +725,7 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver intel_pstate_driver = {
> -	.flags		= CPUFREQ_CONST_LOOPS,
> +	.flags		= CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= intel_pstate_verify_policy,
>  	.setpolicy	= intel_pstate_set_policy,
>  	.get		= intel_pstate_get,
> diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
> index 45bafdd..16c0a37 100644
> --- a/drivers/cpufreq/longhaul.c
> +++ b/drivers/cpufreq/longhaul.c
> @@ -909,6 +909,7 @@ static int longhaul_cpu_init(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver longhaul_driver = {
> +	.flags	= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify	= cpufreq_generic_frequency_table_verify,
>  	.target_index = longhaul_target,
>  	.get	= longhaul_get,
> diff --git a/drivers/cpufreq/longrun.c b/drivers/cpufreq/longrun.c
> index 074971b..b67d341 100644
> --- a/drivers/cpufreq/longrun.c
> +++ b/drivers/cpufreq/longrun.c
> @@ -278,7 +278,7 @@ static int longrun_cpu_init(struct cpufreq_policy *policy)
>  
>  
>  static struct cpufreq_driver longrun_driver = {
> -	.flags		= CPUFREQ_CONST_LOOPS,
> +	.flags		= CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= longrun_verify_policy,
>  	.setpolicy	= longrun_set_policy,
>  	.get		= longrun_get,
> diff --git a/drivers/cpufreq/p4-clockmod.c b/drivers/cpufreq/p4-clockmod.c
> index 3d1cba9..92b7e2b 100644
> --- a/drivers/cpufreq/p4-clockmod.c
> +++ b/drivers/cpufreq/p4-clockmod.c
> @@ -234,6 +234,7 @@ static unsigned int cpufreq_p4_get(unsigned int cpu)
>  }
>  
>  static struct cpufreq_driver p4clockmod_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= cpufreq_p4_target,
>  	.init		= cpufreq_p4_cpu_init,
> diff --git a/drivers/cpufreq/pcc-cpufreq.c b/drivers/cpufreq/pcc-cpufreq.c
> index e2b4f40..eafe4ca 100644
> --- a/drivers/cpufreq/pcc-cpufreq.c
> +++ b/drivers/cpufreq/pcc-cpufreq.c
> @@ -571,7 +571,7 @@ static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver pcc_cpufreq_driver = {
> -	.flags = CPUFREQ_CONST_LOOPS,
> +	.flags = CPUFREQ_CONST_LOOPS | CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.get = pcc_get_freq,
>  	.verify = pcc_cpufreq_verify,
>  	.target = pcc_cpufreq_target,
> diff --git a/drivers/cpufreq/powernow-k6.c b/drivers/cpufreq/powernow-k6.c
> index 643e795..fe60021 100644
> --- a/drivers/cpufreq/powernow-k6.c
> +++ b/drivers/cpufreq/powernow-k6.c
> @@ -150,6 +150,7 @@ static unsigned int powernow_k6_get(unsigned int cpu)
>  }
>  
>  static struct cpufreq_driver powernow_k6_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= powernow_k6_target,
>  	.init		= powernow_k6_cpu_init,
> diff --git a/drivers/cpufreq/powernow-k7.c b/drivers/cpufreq/powernow-k7.c
> index 946708a..4e67abc 100644
> --- a/drivers/cpufreq/powernow-k7.c
> +++ b/drivers/cpufreq/powernow-k7.c
> @@ -679,6 +679,7 @@ static int powernow_cpu_exit(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver powernow_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= powernow_target,
>  	.get		= powernow_get,
> diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c
> index 0023c7d..ffe89ba 100644
> --- a/drivers/cpufreq/powernow-k8.c
> +++ b/drivers/cpufreq/powernow-k8.c
> @@ -1204,7 +1204,8 @@ out:
>  }
>  
>  static struct cpufreq_driver cpufreq_amd64_driver = {
> -	.flags		= CPUFREQ_ASYNC_NOTIFICATION,
> +	.flags		= CPUFREQ_ASYNC_NOTIFICATION |
> +				CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= powernowk8_target,
>  	.bios_limit	= acpi_processor_get_bios_limit,
> diff --git a/drivers/cpufreq/sc520_freq.c b/drivers/cpufreq/sc520_freq.c
> index 6adb354..d6a1cf6 100644
> --- a/drivers/cpufreq/sc520_freq.c
> +++ b/drivers/cpufreq/sc520_freq.c
> @@ -89,6 +89,7 @@ static int sc520_freq_cpu_init(struct cpufreq_policy *policy)
>  
>  
>  static struct cpufreq_driver sc520_freq_driver = {
> +	.flags	= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.get	= sc520_freq_get_cpu_frequency,
>  	.verify	= cpufreq_generic_frequency_table_verify,
>  	.target_index = sc520_freq_target,
> diff --git a/drivers/cpufreq/speedstep-centrino.c b/drivers/cpufreq/speedstep-centrino.c
> index 4e1daca..887fd43 100644
> --- a/drivers/cpufreq/speedstep-centrino.c
> +++ b/drivers/cpufreq/speedstep-centrino.c
> @@ -505,6 +505,7 @@ out:
>  }
>  
>  static struct cpufreq_driver centrino_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.name		= "centrino", /* should be speedstep-centrino,
>  					 but there's a 16 char limit */
>  	.init		= centrino_cpu_init,
> diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
> index 7639b2b..67596e7 100644
> --- a/drivers/cpufreq/speedstep-ich.c
> +++ b/drivers/cpufreq/speedstep-ich.c
> @@ -307,6 +307,7 @@ static int speedstep_cpu_init(struct cpufreq_policy *policy)
>  
>  
>  static struct cpufreq_driver speedstep_driver = {
> +	.flags	= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.name	= "speedstep-ich",
>  	.verify	= cpufreq_generic_frequency_table_verify,
>  	.target_index = speedstep_target,
> diff --git a/drivers/cpufreq/speedstep-smi.c b/drivers/cpufreq/speedstep-smi.c
> index 0f5326d..4f23289 100644
> --- a/drivers/cpufreq/speedstep-smi.c
> +++ b/drivers/cpufreq/speedstep-smi.c
> @@ -308,6 +308,7 @@ static int speedstep_resume(struct cpufreq_policy *policy)
>  }
>  
>  static struct cpufreq_driver speedstep_driver = {
> +	.flags		= CPUFREQ_SKIP_INITIAL_FREQ_CHECK,
>  	.name		= "speedstep-smi",
>  	.verify		= cpufreq_generic_frequency_table_verify,
>  	.target_index	= speedstep_target,
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.

Re: [PATCH V3 2/2] cpufreq: Mark x86 drivers with CPUFREQ_SKIP_INITIAL_FREQ_CHECK flag

[Viresh Kumar]

On Fri, Nov 29, 2013 at 7:25 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> I think you haven't missed any of them.
>
> That said, you need to do this in patch [1/2], or the kernel between
> patches [1/2] and [2/2] may be broken on some systems.
>
> If you want to do that in separate patches, the current [2/2] should be
> [1/2] and vice versa.
>
> I guess they will apply in the reverse order?

No, definition of CPUFREQ_SKIP_INITIAL_FREQ_CHECK would be
missing then after the first patch..

Anyway, I have fixed that and resent them now..