From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Fri, 01 Aug 2014 12:12:58 +0100 Subject: [PATCH] ARM: multi_v7_defconfig: major refresh In-Reply-To: References: <1406052070-6207-1-git-send-email-olof@lixom.net> <53DB6B4F.9080605@arm.com> <1406890899.2794.40.camel@linaro1.home> Message-ID: <53DB763A.10306@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 01/08/14 12:03, Olof Johansson wrote: > On Fri, Aug 1, 2014 at 4:01 AM, Jon Medhurst (Tixy) 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 >>> [...] >> >>>> +CONFIG_BIG_LITTLE=y >>>> +CONFIG_BL_SWITCHER=y >>> >>> 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? > > +1. > >> >>> 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. Regards, Sudeep