From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: CPUIdle for Exynos5422 Odroid-XU3/XU4 boards. Date: Fri, 28 Aug 2015 21:42:35 +0900 Message-ID: <55E0573B.4060604@samsung.com> References: <4468206.R1amSm9GHX@amdc1976> <20150825160932.GD20070@red-moon> <1574385.AV2PKdoIbr@amdc1976> <55E01D61.8020706@osg.samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:33903 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752036AbbH1Mmm (ORCPT ); Fri, 28 Aug 2015 08:42:42 -0400 In-Reply-To: <55E01D61.8020706@osg.samsung.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Javier Martinez Canillas , Bartlomiej Zolnierkiewicz , Lorenzo Pieralisi Cc: Anand Moon , Daniel Lezcano , Kukjin Kim , "linux-samsung-soc@vger.kernel.org" , Przemyslaw Marczak , Kevin Hilman , "linux-pm@vger.kernel.org" W dniu 28.08.2015 o 17:35, Javier Martinez Canillas pisze: > Hello Bartlomiej and Lorenzo, > > Thanks a lot for your explanations. > > On 08/27/2015 06:58 PM, Bartlomiej Zolnierkiewicz wrote: > >> If somebody wants to implement a separate Exynos542x/Exynos5800 >> big.LITTLE cpuidle driver for them I see no problem with it and I'm >> willing to help in maintaining it. >> > > Ok, I'll see if I can take a look what is needed to implement a Exynos542x CPUidle > driver. I'm quite busy with other stuff right now but I should be less busy in a > couple of weeks. The only useful users of Exynos542x cpuidle would be Chromebooks. Probably the same goes with suspend to RAM. Non-mobile devices could leave without it. In the same time cpuidle and S2R would require a significant amount of work. Testing would have to be performed on Chromebooks. I have doubts it would work on Odroid XU3. I dug into S2R issues on Odroid XU3 and after fixing trivial imprecise abort I don't have clue. It just dies somewhere in firmware/bootloader. Vendor code has a lot more stuff related to suspend and testing it one-by-one whether it fixes the issue is frustrating. Do we really need cpuidle or S2R on Exynos542x/5800? > > Maybe is a little bit out of topic but since Anand also asked about CPUFreq support, > are you planning on re-posting your "cpufreq: add generic cpufreq driver support > for Exynos5250/5800 platforms" [0] series? That would be useful. Bartlomiej, do you have plans for continuing the work? Best regards, Krzysztof