The discussion about having different cpus on the system with different latencies bring us to a first attemp by adding a pointer in the cpuidle_device to the states array.
But as Rafael suggested, it would make more sense to create a driver per cpu [1].
This patch adds support for multiple cpuidle drivers.
It creates a per cpu cpuidle driver pointer.
In order to not break the different drivers, the function cpuidle_register_driver assign for each cpu, the driver.
The multiple driver support is optional and if it is not set, the cpuide driver core code remains the same (except some code reorganisation).
I did the following tests compiled, booted, tested without/with CONFIG_CPU_IDLE, with/without CONFIG_CPU_IDLE_MULTIPLE_DRIVERS.
Tested on Core2 Duo T9500 with acpi_idle [and intel_idle] Tested on ARM Dual Cortex-A9 U8500 (aka Snowball)
[1] http://www.spinics.net/lists/linux-acpi/msg37921.html
Daniel Lezcano (4): cpuidle : move driver's refcount to cpuidle cpuidle : move driver checking within the lock section cpuidle - prepare the driver core to be multi drivers aware cpuidle - support multiple drivers
drivers/cpuidle/Kconfig | 9 ++ drivers/cpuidle/cpuidle.c | 24 ++++-- drivers/cpuidle/driver.c | 194 ++++++++++++++++++++++++++++++++++++++------- drivers/cpuidle/sysfs.c | 50 +++++++++--- include/linux/cpuidle.h | 9 ++- 5 files changed, 238 insertions(+), 48 deletions(-)