Re: [PATCH] Re: cpufreq limits avilable frequencies to 800MHz on git kernel

[Thomas Renninger <trenn@suse.de>]

On Friday 18 July 2008 12:41:59 pm Laurence Darby wrote:
> Thomas Renninger wrote:
> > Hi,
> >
> > maybe I found something..., can someone review/test this.
>
> Hi,
>
> I tried this patch, but I don't think it made a difference, ie. _PPC
> still got called before the rest.  Was this meant to fix my E8400 not
> being recognised problem?

Sorry, I not only messed up with mixing up two variables, but also with mailing...

Below  is the one that may work if this really is the problem.

       Thomas

ACPI CPUFREQ: Only call _PPC after cpufreq ACPI init funcs got called already

Ingo Molnar provided a fix to not call _PPC at processor driver initialization time.
Git commit #e4233dec749a3519069d9390561b5636a75c7579

But it can still happen that _PPC is called at  processor driver initialization time.

This patch should make sure that this is not possible anymore.
I am not sure whether this covers all necessary low level drivers, only powernow-kX and acpi-cpufreq seem to call this function, but it
should be fine to test for ThinkPad users.


Signed-off-by: Thomas Renninger <trenn@suse.de>
---
 arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c |    6 ++++++
 drivers/acpi/processor_perflib.c              |   15 +++++++++++++--
 drivers/cpufreq/cpufreq.c                     |    3 +++
 include/linux/cpufreq.h                       |    1 +
 4 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c b/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c
index 69288f6..3233fe8 100644
--- a/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c
+++ b/arch/powerpc/platforms/cell/cbe_cpufreq_pmi.c
@@ -96,6 +96,12 @@ static int pmi_notifier(struct notifier_block *nb,
 	struct cpufreq_frequency_table *cbe_freqs;
 	u8 node;
 
+	/* Should this really be called for CPUFREQ_ADJUST, CPUFREQ_INCOMPATIBLE
+	 * and CPUFREQ_NOTIFY policy events?)
+	 */
+	if (event == CPUFREQ_START)
+		return 0;
+
 	cbe_freqs = cpufreq_frequency_get_table(policy->cpu);
 	node = cbe_cpu_to_node(policy->cpu);
 
diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index b474996..e98071a 100644
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -64,7 +64,13 @@ static DEFINE_MUTEX(performance_mutex);
  * policy is adjusted accordingly.
  */
 
-static unsigned int ignore_ppc = 0;
+/* ignore_ppc:
+ * -1 -> cpufreq low level drivers not initialized -> _PSS, etc. not called yet
+ *       ignore _PPC
+ *  0 -> cpufreq low level drivers initialized -> consider _PPC values
+ *  1 -> ignore _PPC totally -> forced by user through boot param
+ */
+static unsigned int ignore_ppc = -1;
 module_param(ignore_ppc, uint, 0644);
 MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
 		 "limited by BIOS, this should help");
@@ -72,7 +78,7 @@ MODULE_PARM_DESC(ignore_ppc, "If the frequency of your machine gets wrongly" \
 #define PPC_REGISTERED   1
 #define PPC_IN_USE       2
 
-static int acpi_processor_ppc_status = 0;
+static int acpi_processor_ppc_status;
 
 static int acpi_processor_ppc_notifier(struct notifier_block *nb,
 				       unsigned long event, void *data)
@@ -81,6 +87,11 @@ static int acpi_processor_ppc_notifier(struct notifier_block *nb,
 	struct acpi_processor *pr;
 	unsigned int ppc = 0;
 
+	if (event == CPUFREQ_START && ignore_ppc <= 0) {
+		ignore_ppc = 0;
+		return 0;
+	}
+
 	if (ignore_ppc)
 		return 0;
 
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 1d41496..0471ef5 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -825,6 +825,9 @@ static int cpufreq_add_dev(struct sys_device *sys_dev)
 	policy->user_policy.min = policy->cpuinfo.min_freq;
 	policy->user_policy.max = policy->cpuinfo.max_freq;
 
+	blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+				     CPUFREQ_START, policy);
+
 #ifdef CONFIG_SMP
 
 #ifdef CONFIG_HOTPLUG_CPU
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index e7e91db..07cb761 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -109,6 +109,7 @@ struct cpufreq_policy {
 #define CPUFREQ_ADJUST		(0)
 #define CPUFREQ_INCOMPATIBLE	(1)
 #define CPUFREQ_NOTIFY		(2)
+#define CPUFREQ_START		(3)
 
 #define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
 #define CPUFREQ_SHARED_TYPE_HW	 (1) /* HW does needed coordination */
-- 
1.5.4.5