On 03/08/15 18:29, Ashwin Chaugule wrote:
On 20 July 2015 at 10:20, Sudeep Holla sudeep.holla@arm.com wrote:
On 09/07/15 19:04, Ashwin Chaugule wrote:
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 ashwin.chaugule@linaro.org
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 ACPIconfig 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
booldepends on ACPI_PROCESSOR && CPU_FREQselect THERMALhelpThis driver implements ACPI methods for controlling CPUperformance
using PSS methods as described in the ACPI spec. It also enablessupport
for ACPI based performance throttling (TSS) and ACPI basedthermal
monitoring. It is required by several flavors of cpufreqperformance-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.
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