Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751847AbdCCJqP convert rfc822-to-8bit (ORCPT ); Fri, 3 Mar 2017 04:46:15 -0500 Received: from mga04.intel.com ([192.55.52.120]:47600 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751176AbdCCJqO (ORCPT ); Fri, 3 Mar 2017 04:46:14 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,236,1484035200"; d="scan'208";a="1104336075" From: "Patel, Mayurkumar" To: Sinan Kaya , "linux-pci@vger.kernel.org" , "timur@codeaurora.org" , "cov@codeaurora.org" , Bjorn Helgaas CC: "linux-arm-msm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , open list Subject: RE: [PATCH V2] PCI/ASPM: reconfigure ASPM following hotplug for POLICY_DEFAULT Thread-Topic: [PATCH V2] PCI/ASPM: reconfigure ASPM following hotplug for POLICY_DEFAULT Thread-Index: AQHSe/qttcHwVK+D9UySxiqVwThowaF+YrwwgABNHgCAADQfcIABjtUAgAD/8XCAAJX0gIABA3KA Date: Fri, 3 Mar 2017 09:43:43 +0000 Message-ID: <92EBB4272BF81E4089A7126EC1E7B2846666A1D5@IRSMSX101.ger.corp.intel.com> References: <1485891928-14573-1-git-send-email-okaya@codeaurora.org> <92EBB4272BF81E4089A7126EC1E7B2846666830C@IRSMSX101.ger.corp.intel.com> <92EBB4272BF81E4089A7126EC1E7B28466668774@IRSMSX101.ger.corp.intel.com> <92EBB4272BF81E4089A7126EC1E7B28466669BFF@IRSMSX101.ger.corp.intel.com> In-Reply-To: Accept-Language: de-DE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.182] Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4824 Lines: 124 Hi Kaya > >Hi Mayurkumar > >On 3/2/2017 11:05 AM, Patel, Mayurkumar wrote: >>> >>> Hi Bjorn, >>> >>> On 2/28/2017 1:57 PM, Patel, Mayurkumar wrote: >>>>> I was trying to figure out when to use saved values vs. the values in >>>>> registers by looking at the enable_cnt. >>>>> enable_cnt is 0 during boot on my system. >>>> enable_cnt for the root port on my system is set to 1 for "root port" already without saving >>>> any ASPM related settings. >>>> >>>> >>> >>> What would be the best way to figure out when to save power-on values from >>> the registers? >>> >> >> I can upload the diffs) because enable_cnt in pci_enable_device() can be triggered >> from multiple places at boot time so it might not be safe to use it? > >Go ahead and share your diff. It doesn't hurt to look at other alternatives. > So basically, I introduced a new atomic variable to save the aspm_policy for the first time. Below is my diff. diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 3dd8bcb..c8e1e3a 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -338,8 +338,9 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint) } } -static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) +static void pcie_aspm_cap_init(struct pci_dev *pdev, int blacklist) { + struct pcie_link_state *link = pdev->link_state; struct pci_dev *child, *parent = link->pdev; struct pci_bus *linkbus = parent->subordinate; struct aspm_register_info upreg, dwreg; @@ -397,8 +398,21 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1); link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1); - /* Save default state */ - link->aspm_default = link->aspm_enabled; + /* + * Save default state from FW when enabling ASPM for the first time + * during boot by looking at the calculated link->aspm_enabled bits + * above and aspm_enable_cnt will be zero. + * + * If this path is getting called for the second/third time + * (aspm_enable_cnt will be non-zero). Assume that the current state + * of the ASPM registers may not necessarily match what FW asked us to + * do as in the case of hotplug insertion/removal. + */ + if (atomic_inc_return(&pdev->aspm_enable_cnt) == 1) + pdev->aspm_default = link->aspm_default = link->aspm_enabled; + else + link->aspm_default = pdev->aspm_default; + /* Setup initial capable state. Will be updated later */ link->aspm_capable = link->aspm_support; @@ -606,7 +620,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev) * upstream links also because capable state of them can be * update through pcie_aspm_cap_init(). */ - pcie_aspm_cap_init(link, blacklist); + pcie_aspm_cap_init(pdev, blacklist); /* Setup initial Clock PM state */ pcie_clkpm_cap_init(link, blacklist); diff --git a/include/linux/pci.h b/include/linux/pci.h index e2d1a12..aa7bd7e 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -321,6 +321,8 @@ struct pci_dev { #ifdef CONFIG_PCIEASPM struct pcie_link_state *link_state; /* ASPM link state */ + unsigned int aspm_default; /* ASPM policy set by BIOS */ + atomic_t aspm_enable_cnt; /* ASPM policy initialization */ #endif pci_channel_state_t error_state; /* current connectivity state */ >> >> @Kaya/Bjorn: Do you have any other suggestions or Could you also please help by comment what would make sense? >> >> >>> -- >>> Sinan Kaya >>> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. >>> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. >> Intel Deutschland GmbH >> Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany >> Tel: +49 89 99 8853-0, www.intel.de >> Managing Directors: Christin Eisenschmid, Christian Lamprechter >> Chairperson of the Supervisory Board: Nicole Lau >> Registered Office: Munich >> Commercial Register: Amtsgericht Muenchen HRB 186928 >> >> > > >-- >Sinan Kaya >Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. >Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. Intel Deutschland GmbH Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany Tel: +49 89 99 8853-0, www.intel.de Managing Directors: Christin Eisenschmid, Christian Lamprechter Chairperson of the Supervisory Board: Nicole Lau Registered Office: Munich Commercial Register: Amtsgericht Muenchen HRB 186928