diff options
| author | Daniel Lezcano <daniel.lezcano@linaro.org> | 2012-10-31 16:44:48 +0000 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2012-11-15 00:34:23 +0100 |
| commit | bf4d1b5ddb78f86078ac6ae0415802d5f0c68f92 (patch) | |
| tree | 36ec1f061372f6a8cfe7b3326036f06aa3a5067c /drivers/cpuidle/Kconfig | |
| parent | 13dd52f11a04e616900f565d6a1e5138e58d579f (diff) | |
| download | linux-bf4d1b5ddb78f86078ac6ae0415802d5f0c68f92.tar.gz | |
cpuidle: support multiple drivers
With the tegra3 and the big.LITTLE [1] new architectures, several cpus with different characteristics (latencies and states) can co-exists on the system. The cpuidle framework has the limitation of handling only identical cpus. This patch removes this limitation by introducing the multiple driver support for cpuidle. This option is configurable at compile time and should be enabled for the architectures mentioned above. So there is no impact for the other platforms if the option is disabled. The option defaults to 'n'. Note the multiple drivers support is also compatible with the existing drivers, even if just one driver is needed, all the cpu will be tied to this driver using an extra small chunk of processor memory. The multiple driver support use a per-cpu driver pointer instead of a global variable and the accessor to this variable are done from a cpu context. In order to keep the compatibility with the existing drivers, the function 'cpuidle_register_driver' and 'cpuidle_unregister_driver' will register the specified driver for all the cpus. The semantic for the output of /sys/devices/system/cpu/cpuidle/current_driver remains the same except the driver name will be related to the current cpu. The /sys/devices/system/cpu/cpu[0-9]/cpuidle/driver/name files are added allowing to read the per cpu driver name. [1] http://lwn.net/Articles/481055/ Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle/Kconfig')
| -rw-r--r-- | drivers/cpuidle/Kconfig | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index a76b689e553b..234ae651b38f 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -9,6 +9,15 @@ config CPU_IDLE If you're using an ACPI-enabled platform, you should say Y here. +config CPU_IDLE_MULTIPLE_DRIVERS + bool "Support multiple cpuidle drivers" + depends on CPU_IDLE + default n + help + Allows the cpuidle framework to use different drivers for each CPU. + This is useful if you have a system with different CPU latencies and + states. If unsure say N. + config CPU_IDLE_GOV_LADDER bool depends on CPU_IDLE |