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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 B1900C4338F for ; Tue, 24 Aug 2021 00:43:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 80E68613A7 for ; Tue, 24 Aug 2021 00:43:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233260AbhHXAn6 (ORCPT ); Mon, 23 Aug 2021 20:43:58 -0400 Received: from mga18.intel.com ([134.134.136.126]:60583 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233101AbhHXAn6 (ORCPT ); Mon, 23 Aug 2021 20:43:58 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10085"; a="204344167" X-IronPort-AV: E=Sophos;i="5.84,346,1620716400"; d="scan'208";a="204344167" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2021 17:43:14 -0700 X-IronPort-AV: E=Sophos;i="5.84,346,1620716400"; d="scan'208";a="535573127" Received: from otc-nc-03.jf.intel.com (HELO otc-nc-03) ([10.54.39.123]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Aug 2021 17:43:14 -0700 Date: Mon, 23 Aug 2021 17:41:01 -0700 From: "Raj, Ashok" To: Jon Derrick Cc: linux-pci@vger.kernel.org, Bjorn Helgaas , Lukas Wunner , jonathan.derrick@linux.dev, James Puthukattukaran , Ashok Raj Subject: Re: [PATCH v2] PCI: pciehp: Quirk to ignore spurious DLLSC when off Message-ID: <20210824004101.GA67273@otc-nc-03> References: <20210823184919.3412-1-jonathan.derrick@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210823184919.3412-1-jonathan.derrick@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Aug 23, 2021 at 12:49:19PM -0600, Derrick, Jonathan wrote: > From: James Puthukattukaran > > When a specific x8 CEM card is bifurcated into x4x4 mode, and the > upstream ports both support hotplugging on each respective x4 device, a > slot management system for the CEM card requires both x4 devices to be > sysfs removed from the OS before it can safely turn-off physical power. sysfs removed from the OS seems a bit confusing.. Do you mean removed via sysfs by echo 0 > power? > The implications are that Slot Control will display Powered Off status > for the device where the device is actually powered until both ports > have powered off. > > When power is removed from the first half, real power and link remains > active while waiting for the second half to have power removed. When > power is then removed from the second half, the first half starts > shutdown sequence and will trigger a DLLSC event. This is misinterpreted > as an enabling event and causes the first half to be re-enabled. > > The spurious enable can be resolved by ignoring link status change > events when no link is active when in the off state. This patch adds a > quirk for the card. > > Acked-by: Jon Derrick > Signed-off-by: James Puthukattukaran > --- > v1->v2: Device-specific quirk > > drivers/pci/hotplug/pciehp_ctrl.c | 7 +++++++ > drivers/pci/quirks.c | 30 ++++++++++++++++++++++++++++++ > include/linux/pci.h | 1 + > 3 files changed, 38 insertions(+) > > diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c > index 529c34808440..db41f78bfac8 100644 > --- a/drivers/pci/hotplug/pciehp_ctrl.c > +++ b/drivers/pci/hotplug/pciehp_ctrl.c > @@ -225,6 +225,7 @@ void pciehp_handle_disable_request(struct controller *ctrl) > void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) > { > int present, link_active; > + struct pci_dev *pdev = ctrl->pcie->port; > > /* > * If the slot is on and presence or link has changed, turn it off. > @@ -265,6 +266,12 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events) > cancel_delayed_work(&ctrl->button_work); > fallthrough; > case OFF_STATE: > + if (pdev->shared_pcc_and_link_slot && > + (events & PCI_EXP_SLTSTA_DLLSC) && !link_active) { Is it !link_active? Based on the explanation, until we turn off both slots you would see link is still active correct? > + mutex_unlock(&ctrl->state_lock); > + break; > + } > +