On 7 July 2015 at 21:07, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote: > On Monday, June 15, 2015 04:09:06 PM Ashwin Chaugule wrote: >> The ACPI processor driver is currently tied too closely >> to the ACPI C-states (CST), P-states (PSS) and other related >> constructs for controlling CPU idle and CPU performance. >> >> The newer ACPI specification (v5.1 onwards) introduces >> alternative methods to CST and 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 two new Kconfig symbols to allow for >> finer configurability among the various options for controlling >> CPU idle and performance states. There is no change in functionality >> and these options are defaulted to enabled to maintain previous >> behaviour. >> >> 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@xxxxxxxxxx> >> Reviewed-by: Al Stone <al.stone@xxxxxxxxxx> >> --- >> drivers/acpi/Kconfig | 31 +++++++++-- >> drivers/acpi/Makefile | 7 ++- >> drivers/acpi/processor_driver.c | 86 ++++++++++++++++++---------- >> drivers/cpufreq/Kconfig | 2 +- >> drivers/cpufreq/Kconfig.x86 | 2 + >> include/acpi/processor.h | 120 ++++++++++++++++++++++++++++------------ >> 6 files changed, 176 insertions(+), 72 deletions(-) >> >> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig >> index ab2cbb5..5942754 100644 >> --- a/drivers/acpi/Kconfig >> +++ b/drivers/acpi/Kconfig >> @@ -166,18 +166,39 @@ 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_PROCESSOR >> - tristate "Processor" >> - select THERMAL >> - select CPU_IDLE >> +config ACPI_CST >> + bool "ACPI C states (CST) driver" >> + depends on ACPI_PROCESSOR >> depends on X86 || IA64 >> + select CPU_IDLE >> default y >> help >> This driver installs ACPI as the idle handler for Linux and uses >> ACPI C2 and C3 processor states to save power on systems that >> - support it. It is required by several flavors of cpufreq >> + support it. >> + >> +config ACPI_PSS >> + bool "ACPI P States (PSS) driver" >> + depends on ACPI_PROCESSOR >> + depends on X86 || IA64 >> + select THERMAL >> + default y >> + 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. > > For starters, I don't like these new Kconfig options. > > Isn't there a way to implement what you need without adding them? We need to use the ACPI Processor driver for CPPC without including all its current dependencies. (i.e. PSS, TSS, CSS etc.). The upcoming LPI work from Sudeep will also face the same issue. I considered the alternative of adding a probe routine which matches ACPI_PROCESSOR_OBJECT/DEVICE_HID to each driver, but this seemed like a better option. Do you have any other ideas? Thanks, Ashwin. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
