[PATCH] ARM: multi_v7_defconfig: major refresh
sudeep.holla at arm.com
Fri Aug 1 04:12:58 PDT 2014
On 01/08/14 12:03, Olof Johansson wrote:
> On Fri, Aug 1, 2014 at 4:01 AM, Jon Medhurst (Tixy) <tixy at linaro.org> wrote:
>> On Fri, 2014-08-01 at 11:26 +0100, Sudeep Holla wrote:
>>> On 22/07/14 19:01, Olof Johansson wrote:
>>>> This is a major refresh of the multi_v7_defconfig:
>>>> - Bring over a bunch of Samsung drivers to make ODROID-U3 and Chromebooks usable
>>>> * Enable big.LITTLE
>>>> * MCPM
>>> IIUC, this will enable switcher code by default. I am not sure if this
>>> is intentional ? E.g.: After this I can have only 2 active cpus instead
>>> of 5 on my Vexpress TC2 platform.
>>> IMO we can keep this enabled by default in the build, but disabled
>>> by default on boot.
>> TC2 has a big.LITTLE processor and the switcher is the only mainlined
>> way of making any kind of proper use of big.LITTLE, so why not have it
>> enabled by default?
>>> One way to achieve this:
>>> (There's sysfs to re-enable it runtime)
>> The opposite is also true, if you don't want the switcher enabled you
>> can disable it by the same method after boot ;-)
>>> diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
>>> index 490f3dced749..f4c36e70166a 100644
>>> --- a/arch/arm/common/bL_switcher.c
>>> +++ b/arch/arm/common/bL_switcher.c
>>> @@ -794,7 +794,7 @@ static int bL_switcher_hotplug_callback(struct
>>> notifier_block *nfb,
>>> return NOTIFY_DONE;
>>> -static bool no_bL_switcher;
>>> +static bool no_bL_switcher = true;
>> This changes the default for everyone, which I guess is fair enough if
>> there is a good reason, but I'm not sure there is.
> No, I don't think there is.
It's just that people using TC2 will suddenly see 3 of the 5 CPUs missing.
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