From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH 1/2] drivers: amba: properly handle devices with power domains Date: Thu, 26 Nov 2015 13:33:35 +0100 Message-ID: <5656FC1F.6060705@samsung.com> References: <1448456127-31842-1-git-send-email-m.szyprowski@samsung.com> <1448456289-31960-1-git-send-email-m.szyprowski@samsung.com> <20151125132458.GL8644@n2100.arm.linux.org.uk> <5655B8F6.1070104@samsung.com> <20151125180953.GN8644@n2100.arm.linux.org.uk> <5656C527.8040804@samsung.com> <20151126105945.GZ8644@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mailout4.w1.samsung.com ([210.118.77.14]:53470 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751019AbbKZMdj (ORCPT ); Thu, 26 Nov 2015 07:33:39 -0500 Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout4.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NYF008RW9K0NYA0@mailout4.w1.samsung.com> for linux-samsung-soc@vger.kernel.org; Thu, 26 Nov 2015 12:33:36 +0000 (GMT) In-reply-to: <20151126105945.GZ8644@n2100.arm.linux.org.uk> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Russell King - ARM Linux , Ulf Hansson Cc: Krzysztof Kozlowski , linux-samsung-soc , Kukjin Kim , "linux-arm-kernel@lists.infradead.org" , Bartlomiej Zolnierkiewicz Hello, On 2015-11-26 11:59, Russell King - ARM Linux wrote: > On Thu, Nov 26, 2015 at 11:24:50AM +0100, Ulf Hansson wrote: >> On 26 November 2015 at 09:39, Marek Szyprowski wrote: >>> Hello, >>> >>> On 2015-11-25 19:09, Russell King - ARM Linux wrote: >>>> On Wed, Nov 25, 2015 at 02:56:10PM +0100, Ulf Hansson wrote: >>>>> On 25 November 2015 at 14:34, Marek Szyprowski >>>>> wrote: >>>>>> Is ignoring dev_pm_domain_attach() return value a solution for you? >>>>> That's probably better than nothing, but I wonder if it in practice >>>>> will have any effect? >>>> If the PM domain is down, then trying to tread the ID is likely to oops >>>> the kernel. >>> >>> In my case kernel simply hangs (no single message, even when earlyprintk is >>> enabled) >>> instead of oopsing, that's why I've submitted this patch. >>> >> Okay. >> >> I suggest we go ahead and try that approach (ignoring the return >> value). It's "quick fix", but the easiest way forward to solve the >> problem. >> >> My only concern is if such change impacts the boot time. We should do >> some tests to see if the change is negligible, if not we should >> probably think of something else (like keeping the PM domain powered >> until late_init). >> >> Russell, what do you think? > I thought someone had a patch to read the ID during the match callback? Okay, I've reused that patch and it seems to solve mthisproblem. I will send v2 in a few minutes. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Thu, 26 Nov 2015 13:33:35 +0100 Subject: [PATCH 1/2] drivers: amba: properly handle devices with power domains In-Reply-To: <20151126105945.GZ8644@n2100.arm.linux.org.uk> References: <1448456127-31842-1-git-send-email-m.szyprowski@samsung.com> <1448456289-31960-1-git-send-email-m.szyprowski@samsung.com> <20151125132458.GL8644@n2100.arm.linux.org.uk> <5655B8F6.1070104@samsung.com> <20151125180953.GN8644@n2100.arm.linux.org.uk> <5656C527.8040804@samsung.com> <20151126105945.GZ8644@n2100.arm.linux.org.uk> Message-ID: <5656FC1F.6060705@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello, On 2015-11-26 11:59, Russell King - ARM Linux wrote: > On Thu, Nov 26, 2015 at 11:24:50AM +0100, Ulf Hansson wrote: >> On 26 November 2015 at 09:39, Marek Szyprowski wrote: >>> Hello, >>> >>> On 2015-11-25 19:09, Russell King - ARM Linux wrote: >>>> On Wed, Nov 25, 2015 at 02:56:10PM +0100, Ulf Hansson wrote: >>>>> On 25 November 2015 at 14:34, Marek Szyprowski >>>>> wrote: >>>>>> Is ignoring dev_pm_domain_attach() return value a solution for you? >>>>> That's probably better than nothing, but I wonder if it in practice >>>>> will have any effect? >>>> If the PM domain is down, then trying to tread the ID is likely to oops >>>> the kernel. >>> >>> In my case kernel simply hangs (no single message, even when earlyprintk is >>> enabled) >>> instead of oopsing, that's why I've submitted this patch. >>> >> Okay. >> >> I suggest we go ahead and try that approach (ignoring the return >> value). It's "quick fix", but the easiest way forward to solve the >> problem. >> >> My only concern is if such change impacts the boot time. We should do >> some tests to see if the change is negligible, if not we should >> probably think of something else (like keeping the PM domain powered >> until late_init). >> >> Russell, what do you think? > I thought someone had a patch to read the ID during the match callback? Okay, I've reused that patch and it seems to solve mthisproblem. I will send v2 in a few minutes. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland