On 07/28/2013 11:22 AM, Tomasz Figa wrote: > On Sunday 28 of July 2013 09:10:09 Daniel Lezcano wrote: >> On 07/24/2013 01:47 PM, Kukjin Kim wrote: >>> Amit Daniel Kachhap wrote: >>>> This patch skips the deep C1(AFTR -Arm off top running) state for >>>> exynos5440 >>>> soc as this soc does not support this state. All the cpu's only >>>> allows the basic >>>> C0 state. >>>> >>>> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx> >>>> --- >>>> >>>> arch/arm/mach-exynos/cpuidle.c | 2 +- >>>> 1 files changed, 1 insertions(+), 1 deletions(-) >>>> >>>> diff --git a/arch/arm/mach-exynos/cpuidle.c b/arch/arm/mach- >>>> exynos/cpuidle.c >>>> index 17a18ff..9a776a1 100644 >>>> --- a/arch/arm/mach-exynos/cpuidle.c >>>> +++ b/arch/arm/mach-exynos/cpuidle.c >>>> @@ -210,7 +210,7 @@ static int __init exynos4_init_cpuidle(void) >>>> >>>> device->cpu = cpu_id; >>>> >>>> /* Support IDLE only */ >>>> >>>> - if (cpu_id != 0) >>>> + if (soc_is_exynos5440() || cpu_id != 0) >>>> >>>> device->state_count = 1; >>>> >>>> ret = cpuidle_register_device(device); >>>> >>>> -- >>>> 1.7.1 >>> >>> Applied, thanks. >> >> You shouldn't have. This patch means exynos5540 has no cpuidle driver at >> all. It should be fixed in the Kconfig to unselect CONFIG_CPU_IDLE for >> an exynos5540. > > To shed more light on this, let me add that you need to register a cpuidle > driver only if you have more states than a simple WFI or you need some > crazy steps to enter WFI. Default setup falls back to generic ARM WFI. > (Daniel, do we get the nice idle stats as provided by cpuidle core then?) Nope, but with one state, idle vs busy stats do the trick. BTW, I am writing a tool to do some stats based on the idle events [1]. It is still at a very early development stage but we can get some interesting informations. > Anyway, Exynos cpuidle is using an initcall to initialize and we support > multiple Exynos SoCs in single zImage, so deselecting CONFIG_CPU_IDLE is > not an option. Good point. > Considering multiplatform requirements, the driver has to > be modified to initialize only on supported platforms, either by: > > a) dropping the initcall and calling the init function directly from > arch/arm/mach-exynos > > or > > b) checking if machine we are running on is supported, which would mean a > long list of all Exynos SoCs that needs to be checked. > > An evolution of option a) is registering a platform device somewhere in > arch/arm/mach-exynos and making exynos-cpuidle a platform driver. Yes, I am favorable to this solution [2]. > The > problem is that you must register a static platform device from arch code, > because cpuidle is not a real hardware block that can be put into device > tree. Thanks -- Daniel [1] https://git.linaro.org/gitweb?p=people/dlezcano/idlestat.git;a=summary [2] http://patches.linaro.org/18368/ -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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