On 11/4/2024 10:55, Rafael J. Wysocki wrote:
On Sat, Nov 2, 2024 at 4:24 AM Mario Limonciello <superm1@xxxxxxxxxx> wrote:
From: Mario Limonciello <mario.limonciello@xxxxxxx>
arch_init_invariance_cppc() is called at the end of
acpi_cppc_processor_probe() in order to configure frequency invariance
based upon the values from _CPC.
This however doesn't work on AMD CPPC shared memory designs that have
AMD preferred cores enabled because _CPC needs to be analyzed from all
cores to judge if preferred cores are enabled.
This issue manifests to users as a warning since commit 21fb59ab4b97
("ACPI: CPPC: Adjust debug messages in amd_set_max_freq_ratio() to warn"):
```
Could not retrieve highest performance (-19)
```
However the warning isn't the cause of this, it was actually
commit 279f838a61f9 ("x86/amd: Detect preferred cores in
amd_get_boost_ratio_numerator()") which exposed the issue.
To fix this problem, push the call to the arch_init_invariance_cppc()
macro to the end of acpi_processor_driver_init().
Fixes: 279f838a61f9 ("x86/amd: Detect preferred cores in amd_get_boost_ratio_numerator()")
Reported-by: Ivan Shapovalov <intelfx@xxxxxxxxxxxx>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219431
Tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx>
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v1->v2:
* Fix LKP robot issue when CONFIG_ACPI_CPPC_LIB not defined
---
arch/x86/include/asm/topology.h | 2 ++
drivers/acpi/cppc_acpi.c | 6 ------
drivers/acpi/processor_driver.c | 1 +
3 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index abe3a8f22cbd..b04c5db7e945 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -295,6 +295,8 @@ extern void arch_scale_freq_tick(void);
#ifdef CONFIG_ACPI_CPPC_LIB
void init_freq_invariance_cppc(void);
#define arch_init_invariance_cppc init_freq_invariance_cppc
+#else
+static inline void arch_init_invariance_cppc(void) { }
#endif
#endif /* _ASM_X86_TOPOLOGY_H */
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index ed91dfd4fdca..9d48cd706659 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -671,10 +671,6 @@ static int pcc_data_alloc(int pcc_ss_id)
* )
*/
-#ifndef arch_init_invariance_cppc
-static inline void arch_init_invariance_cppc(void) { }
-#endif
-
/**
* acpi_cppc_processor_probe - Search for per CPU _CPC objects.
* @pr: Ptr to acpi_processor containing this CPU's logical ID.
@@ -905,8 +901,6 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
goto out_free;
}
- arch_init_invariance_cppc();
-
kfree(output.pointer);
return 0;
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index cb52dd000b95..59620e7bc664 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -270,6 +270,7 @@ static int __init acpi_processor_driver_init(void)
NULL, acpi_soft_cpu_dead);
acpi_processor_throttling_init();
+ arch_init_invariance_cppc();
return 0;
err:
driver_unregister(&acpi_processor_driver);
--
Applied as a fix for 6.12-rc7.
However, it would be good to add a comment explaining why
acpi_processor_driver_init() calls arch_init_invariance_cppc() at the
end. The ACPI processor driver and CPPC are not otherwise related I
think?
Sure, I'm thinking a comment like this.
/*
* Frequency invariance calculations on AMD platforms can't be run until
* _CPC has been evaluated on all processors which will only happen
* after probing is complete.
*/
If that sounds good do you want to squash it in? Or if you would prefer
another commit tacked on that's no problem I'll do that.
