On 03/08/15 18:29, Ashwin Chaugule wrote:

On 20 July 2015 at 10:20, Sudeep Holla [off-list ref] wrote:

quoted

On 09/07/15 19:04, Ashwin Chaugule wrote:

quoted

The ACPI processor driver is currently tied too closely
to the ACPI P-states (PSS) and other related constructs
for controlling CPU performance.

The newer ACPI specification (v5.1 onwards) introduces
alternative methods to PSS. These new mechanisms are
described within each ACPI Processor object and so they
need to be scanned whenever a new Processor object is detected.
This patch introduces a new Kconfig symbol to allow for
finer configurability among the two options for controlling
performance states. There is no change in functionality and
the option is auto-selected by the architecture Kconfig files.

The following patchwork introduces CPPC: A newer method of
controlling CPU performance. The OS is not expected to support
CPPC and PSS at runtime. So the kconfig option lets us make
these two mutually exclusive at compile time.

Signed-off-by: Ashwin Chaugule <redacted>
---
   arch/x86/Kconfig                |  1 +
   drivers/acpi/Kconfig            | 19 ++++++---
   drivers/acpi/Makefile           |  6 +--
   drivers/acpi/processor_driver.c | 86
+++++++++++++++++++++++++------------
   drivers/cpufreq/Kconfig         |  2 +-
   drivers/cpufreq/Kconfig.x86     |  2 +
   include/acpi/processor.h        | 94
+++++++++++++++++++++++++++--------------
   7 files changed, 142 insertions(+), 68 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 226d569..93d150d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig

@@ -143,6 +143,7 @@ config X86
          select ACPI_LEGACY_TABLES_LOOKUP if ACPI
          select X86_FEATURE_NAMES if PROC_FS
          select SRCU
+       select ACPI_CPU_FREQ_PSS if ACPI

   config INSTRUCTION_DECODER
          def_bool y

diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ab2cbb5..00748dc 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig

@@ -166,17 +166,26 @@ config ACPI_DOCK
            This driver supports ACPI-controlled docking stations and

removable
            drive bays such as the IBM Ultrabay and the Dell Module Bay.

+config ACPI_CPU_FREQ_PSS
+       bool
+       depends on ACPI_PROCESSOR && CPU_FREQ
+       select THERMAL
+       help
+         This driver implements ACPI methods for controlling CPU
performance
+         using PSS methods as described in the ACPI spec. It also enables
support
+         for ACPI based performance throttling (TSS) and ACPI based
thermal
+         monitoring. It is required by several flavors of cpufreq
+         performance-state drivers.
+

Though I agree CPUFreq and the thermal control are related, having _PSS
in config name shouldn't match well IMO. You can have more generic name.

Do you have any suggestions?

No, so I am fine with ACPI_CPU_FREQ_PSS for now, we can change later if
required as along as it's not user-selectable I suppose.

quoted

You are selecting one config while depending on the other, any
particular reason ?

What is the problem? Sorry, I didn't follow.

Just follow what Rafael said, he explained it better than me, I was bit
vague here but implied same thing.

Regards,
Sudeep