From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Figa Subject: Re: [PATCH v9 4/6] ARM: Exynos: switch to using generic cpufreq driver for Exynos4210/5250/5420 Date: Mon, 25 Aug 2014 17:56:36 +0200 Message-ID: <53FB5CB4.4050705@samsung.com> References: <1406707663-16656-1-git-send-email-thomas.ab@samsung.com> <1406707663-16656-5-git-send-email-thomas.ab@samsung.com> <53DA8BB9.6020702@samsung.com> <53DA8D85.3050106@gmail.com> <7hbnrc6px3.fsf@paris.lan> <53F7DA13.6090305@gmail.com> <7h8umc60we.fsf@paris.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mailout3.w1.samsung.com ([210.118.77.13]:47450 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932811AbaHYP4l (ORCPT ); Mon, 25 Aug 2014 11:56:41 -0400 In-reply-to: <7h8umc60we.fsf@paris.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Kevin Hilman , Chander Kashyap , Kukjin Kim , Viresh Kumar Cc: Tomasz Figa , Lukasz Majewski , Mike Turquette , =?windows-1252?Q?Heiko_St=FCbn?= =?windows-1252?Q?er?= , "linux-pm@vger.kernel.org" , Bartlomiej Zolnierkiewicz , amit.kucheria@linaro.org, Chanwoo Choi , Thomas Abraham , "linux-samsung-soc@vger.kernel.org" , linaro-kernel@lists.linaro.org, "linux-arm-kernel@lists.infradead.org" , Marek Szyprowski On 25.08.2014 17:32, Kevin Hilman wrote: > Hi Chander, > > Chander Kashyap writes: > > [...] > >>>> I'm trying it on the 5800/Chromebook2 and it's not terribly stable. I'm >>>> testing along with CPUidle, so there may be some untested interactions >>>> there as it seems a bit more stable without CPUidle enabled. >>>> >>>> I'd love to hear from anyone else that's testing CPUidle and CPUfreq >>>> together big.LITTLE 5420/5800, with or without the switcher. >> >> I have tested this patch series on SMDK5420 with cpuidle (with and >> without b.L switcher enabled). >> >> As of now voltage scaling support is not there in generic big-little >> cpufreq driver (arm_big_little.c). >> Hence need to tie arm and kfc voltages to highest level for testing. > >> Without this change stability issues are there, but with this change >> everything is stable. > > Can you clarify how you're setting the voltages to ensure stability? > > Tomasz, I didn't mean to suggest this isn't ready for mainline. I haven't said that either. I'd just like to know in what state this series is in case of those SoCs. However, if there are stability issues on them, there is also a chance that the same is true for other boards. Anyway, we're early in releasy cycle, so probably we could get better test coverage with this series in linux-next. Kukjin, Viresh, how would you want to proceed with merging it? It touches mach-exynos, cpufreq and samsung-clk, so it is non-trivial to merge. However as far as I can see the cpufreq-related changes are just a number of full file deletes and minor Makefile/Kconfig updates. It will be more difficult with mach-exynos changes, as they are more likely to produce conflict. The only solution that comes to my mind is that I first apply patches 1 and 2, create a stable branch for Kukjin, then he applies patches 3, 4, and 5 and creates a stable branch for me, on top of which I apply patch 6. Best regards, Tomasz