From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A317C433E0 for ; Mon, 15 Jun 2020 15:39:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53D38206D7 for ; Mon, 15 Jun 2020 15:39:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728585AbgFOPjk (ORCPT ); Mon, 15 Jun 2020 11:39:40 -0400 Received: from foss.arm.com ([217.140.110.172]:50562 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728477AbgFOPjj (ORCPT ); Mon, 15 Jun 2020 11:39:39 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9F55F1F1; Mon, 15 Jun 2020 08:39:38 -0700 (PDT) Received: from [10.37.12.69] (unknown [10.37.12.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2F26A3F6CF; Mon, 15 Jun 2020 08:39:36 -0700 (PDT) Subject: Re: Question about Odroid XU4 cpuidle To: Marek Szyprowski , Krzysztof Kozlowski Cc: Bartlomiej Zolnierkiewicz , "linux-samsung-soc@vger.kernel.org" , Andrzej Hajda , s.nawrocki@samsung.com References: <570c73f2-d9d8-4ae1-3caf-829547232e48@arm.com> <20200610140238.GA31473@kozik-lap> <5b6a4345-4df6-51b4-298d-6a4fc6935d89@samsung.com> <8c0a8cc6-9cc0-88b5-6614-67edb903d149@arm.com> <26daae4c-684a-7319-ae6c-f3319ba0406d@samsung.com> From: Lukasz Luba Message-ID: Date: Mon, 15 Jun 2020 16:39:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <26daae4c-684a-7319-ae6c-f3319ba0406d@samsung.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org On 6/15/20 1:45 PM, Marek Szyprowski wrote: > Hi Lukasz > > On 10.06.2020 16:30, Lukasz Luba wrote: >> On 6/10/20 3:09 PM, Marek Szyprowski wrote: >>> On 10.06.2020 16:02, Krzysztof Kozlowski wrote: >>>> On Wed, Jun 10, 2020 at 02:18:12PM +0100, Lukasz Luba wrote: >>>>> Hi Krzysztof, Bartek, >>>>> >>>>> I recall that you have been working on some cpuidle code for >>>>> Exynos(4?). >>>>> >>>>> I have a question regarding CPUIdle driver for Odroid XU4. >>>>> I use the board with LISA tests for EAS, but missing at >>>>> least idle state 0 cause errors (please see the log below). >>>>> >>>>> Currently the system does not report any idle driver and the state 0 >>>>> is missing in: /sys/devices/system/cpu/cpu0/cpuidle/state0/ >>>> The state 0 long time ago was WFI. It was kind of meaningless so it it >>>> was dropped. >>>> >>>>> I am using driver CONFIG_ARM_BIG_LITTLE_CPUIDLE but the >>>>> boot stops silently while trying to init the cpu idle devices in >>>>> there. >>>>> I carry on with a workaround that just removes idle state[1] and set >>>>> state_count=1 in the big and little structures. >>>> Try earlyprintk. >>>> >>>> In general, the big-little cpuidle driver should work... or rather: >>>> long >>>> time ago it was working.  It requires proper support from early stages >>>> (BL1, secure monitor) but this should be already in standard Odroid. >>>> >>>> I just saw there: >>>>     /* Start at index 1, index 0 standard WFI */ >>>> so maybe it was not updated properly to removal of WFI? >>>> >>>> I think no one uses this driver so it might be not well tested and not >>>> that useful. >>> >>> I think it never worked on Odroid XU3/XU4. Afair it was developed on >>> PeachPi Chromebook, which use different bootloader (and doesn't use >>> trustzone). >> >> That would explain the compatibility string in that driver. Good to >> know. Thank you for your response. >> > I've just digged a bit in the old kernels and indeed, the big-little > cpuidle driver worked only on Samsung Exynos 5420/5800 Chromebooks > (Peach Pit/Pi). The last release which worked fine (although it was > still not enabled in the exynos_defconfig) is v4.2. Then it got broken > by the commit 833b5794e330 ("ARM: EXYNOS: reset Little cores when cpu is > up"). It never worked on the Odroid XU3/XU4. Thank you Marek for your time to investigate it. In this case I think there is no way to fix idle state 1 for Odroid xu3/xu4. I don't have Peach Pit/Pi so I have to pass, but I can help you in reviewing if you or someone else have time (and board) to work on it. > > Do you have any plans to fix it? I'm baking some patch internally which might help Odroid XU3/4 though. If that won't be killed, I'll post it soon. If failed internally, I will also let you know. Regards, Lukasz > > Best regards >