From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS Date: Wed, 16 Dec 2015 09:40:50 +0000 Message-ID: <567131A2.6030303@nvidia.com> References: <1449241037-22193-1-git-send-email-jonathanh@nvidia.com> <1449241037-22193-17-git-send-email-jonathanh@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ulf Hansson Cc: Philipp Zabel , Stephen Warren , Thierry Reding , Alexandre Courbot , Rafael Wysocki , Kevin Hilman , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Vince Hsu , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org Hi Ulf, On 15/12/15 19:54, Ulf Hansson wrote: > On 4 December 2015 at 15:57, Jon Hunter wrote: >> Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices >> dependent upon a particular power-domain are only probed when that power >> domain has been powered up, requires that PM is made mandatory for tegra >> 64-bit devices and so select this option for tegra as well. >> >> Signed-off-by: Jon Hunter >> --- >> arch/arm64/Kconfig.platforms | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms >> index 9806324fa215..e0b5bd0aff0f 100644 >> --- a/arch/arm64/Kconfig.platforms >> +++ b/arch/arm64/Kconfig.platforms >> @@ -93,6 +93,8 @@ config ARCH_TEGRA >> select GENERIC_CLOCKEVENTS >> select HAVE_CLK >> select PINCTRL >> + select PM >> + select PM_GENERIC_DOMAINS > > If you still want to allow ARCH_TEGRA to run without PM, you should > probably change to: > > select PM_GENERIC_DOMAINS if PM Per the changelog this is deliberate. If we allow !PM, then there is a potential that you could probe a device when the power domain is not powered on. I understand that some SoCs turn on all the power-domains when !PM but this will not work for tegra because we don't register the power domain until later in the boot and so we are relying upon probe deferral to defer the probe of devices that use power-domains. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934115AbbLPJlB (ORCPT ); Wed, 16 Dec 2015 04:41:01 -0500 Received: from hqemgate16.nvidia.com ([216.228.121.65]:7059 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934016AbbLPJk4 (ORCPT ); Wed, 16 Dec 2015 04:40:56 -0500 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Wed, 16 Dec 2015 01:37:26 -0800 Subject: Re: [PATCH V4 16/16] ARM64: tegra: select PM_GENERIC_DOMAINS To: Ulf Hansson References: <1449241037-22193-1-git-send-email-jonathanh@nvidia.com> <1449241037-22193-17-git-send-email-jonathanh@nvidia.com> CC: Philipp Zabel , Stephen Warren , Thierry Reding , "Alexandre Courbot" , Rafael Wysocki , Kevin Hilman , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Vince Hsu , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-tegra@vger.kernel.org" , "linux-pm@vger.kernel.org" From: Jon Hunter Message-ID: <567131A2.6030303@nvidia.com> Date: Wed, 16 Dec 2015 09:40:50 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.21.132.159] X-ClientProxiedBy: UKMAIL102.nvidia.com (10.26.138.15) To UKMAIL101.nvidia.com (10.26.138.13) Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ulf, On 15/12/15 19:54, Ulf Hansson wrote: > On 4 December 2015 at 15:57, Jon Hunter wrote: >> Enable PM_GENERIC_DOMAINS for tegra 64-bit devices. To ensure that devices >> dependent upon a particular power-domain are only probed when that power >> domain has been powered up, requires that PM is made mandatory for tegra >> 64-bit devices and so select this option for tegra as well. >> >> Signed-off-by: Jon Hunter >> --- >> arch/arm64/Kconfig.platforms | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms >> index 9806324fa215..e0b5bd0aff0f 100644 >> --- a/arch/arm64/Kconfig.platforms >> +++ b/arch/arm64/Kconfig.platforms >> @@ -93,6 +93,8 @@ config ARCH_TEGRA >> select GENERIC_CLOCKEVENTS >> select HAVE_CLK >> select PINCTRL >> + select PM >> + select PM_GENERIC_DOMAINS > > If you still want to allow ARCH_TEGRA to run without PM, you should > probably change to: > > select PM_GENERIC_DOMAINS if PM Per the changelog this is deliberate. If we allow !PM, then there is a potential that you could probe a device when the power domain is not powered on. I understand that some SoCs turn on all the power-domains when !PM but this will not work for tegra because we don't register the power domain until later in the boot and so we are relying upon probe deferral to defer the probe of devices that use power-domains. Cheers Jon