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) | |
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 |