[PATCH] ARM: multi_v7_defconfig: major refresh

Sudeep Holla
2014-08-01T14:57:46Z

On 01/08/14 12:28, Jon Medhurst (Tixy) wrote:
> On Fri, 2014-08-01 at 12:12 +0100, Sudeep Holla wrote:
>>
>> On 01/08/14 12:03, Olof Johansson wrote:
>>> On Fri, Aug 1, 2014 at 4:01 AM, Jon Medhurst (Tixy) <tixy@linaro.org> wrote:
>>>> On Fri, 2014-08-01 at 11:26 +0100, Sudeep Holla wrote:

[...]

>>>>
>>>>> 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 ;-)
>>>>
>>>>> -->8
>>>>> 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.
>
> Yes, if they we're previously using multi_v7_defconfig (do people
> working specifically with TC2's use that?)
>

I don't, but assumed many might use it.

> Conversely, with the change in default proposed above, anyone with their
> own configs enabling the switcher will suddenly see the number of CPUs
> go from 2 to 5. We also have the situation where we have a config
> option, which when enabled, doesn't actually do anything unless the user
> also changes boot arguments or takes measures to enable it after boot.
> Which seems the wrong way for things to work to me.
>

OK, makes sense. Just curious how many big.LITTLE platforms have CPUFreq
support and integrated with bL switcher. Otherwise we end up switching
clusters/cpus using dummy i/f anyways(and probably that's the reason why
that config is enabled which I missed to understand initially as I was
thinking it's more for development and testing only). If is that's
acceptable for those platforms, then it should be fine I believe ?

Regards,
Sudeep