From patchwork Wed Jul 6 12:32:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai-Heng Feng X-Patchwork-Id: 12908086 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF9C1C433EF for ; Wed, 6 Jul 2022 12:33:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231842AbiGFMdq (ORCPT ); Wed, 6 Jul 2022 08:33:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231690AbiGFMdp (ORCPT ); Wed, 6 Jul 2022 08:33:45 -0400 Received: from smtp-relay-canonical-0.canonical.com (smtp-relay-canonical-0.canonical.com [185.125.188.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D399EE04; Wed, 6 Jul 2022 05:33:44 -0700 (PDT) Received: from localhost.localdomain (unknown [10.101.196.174]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-0.canonical.com (Postfix) with ESMTPSA id B0CE441692; Wed, 6 Jul 2022 12:33:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1657110822; bh=Ij7XJmC/+XwLc9RCA+8oEtzYP6f2opNzC/i7DALyxf4=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=N4a6WjFi3HaggQEMc5n/WBnTOkNwycKmXj7W+LLP5Rz4J6dVDd4GLV4FnHAMculYC cux0bvryXmlasULy+7Ni9LuvBbB09oxeyf4PtCJ11nrfllWO6VjAzTY0E7hVhS6fTj mF9YuPnDu5IbgC4fMrGQ66QYwUe1lD1ON/SsBfDVOU0gsUYPpC+D6/pwCQf3sidhgN gMcz/yzneo98haN2J7DDew4Fp1jcFHQa9QGKotyzD53fKVctPFqeNr26BAyGRfEcgc G+LLBsrfRdZpnGuSazTS3bx06e/rGcnnuK6CU7zjmzTSZc8PXr9KwieRTL/P62FYaD mDLAdryM+I2Qg== From: Kai-Heng Feng To: bhelgaas@google.com Cc: mika.westerberg@linux.intel.com, koba.ko@canonical.com, Kai-Heng Feng , "David E . Box" , Sathyanarayanan Kuppuswamy , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] PCI: Disable upstream port PTM during suspend Date: Wed, 6 Jul 2022 20:32:44 +0800 Message-Id: <20220706123244.18056-1-kai.heng.feng@canonical.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Intel Alder Lake platforms, Thunderbolt entering D3cold can cause some errors reported by AER: pcieport 0000:00:1d.0: AER: Uncorrected (Non-Fatal) error received: 0000:00:1d.0 pcieport 0000:00:1d.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID) pcieport 0000:00:1d.0: device [8086:7ab0] error status/mask=00100000/00004000 pcieport 0000:00:1d.0: [20] UnsupReq (First) pcieport 0000:00:1d.0: AER: TLP Header: 34000000 08000052 00000000 00000000 thunderbolt 0000:0a:00.0: AER: can't recover (no error_detected callback) xhci_hcd 0000:3e:00.0: AER: can't recover (no error_detected callback) pcieport 0000:00:1d.0: AER: device recovery failed In addition to that, it can also block system from suspending when a Thunderbolt dock is attached to the same system. The original approach [1] is to disable AER and DPC when link is in L2/L3 Ready, L2 and L3, but Bjorn identified the root cause is the Unsupported Request: - 08:00.0 sent a PTM Request Message (a Posted Request) - 00:1d.0 received the PTM Request Message - The link transitioned to DL_Down - Per sec 2.9.1, 00:1d.0 discarded the Request and reported an Unsupported Request - Or, per sec 6.21.3, if 00:1d.0 received a PTM Request when its own PTM Enable was clear, it would also be treated as an Unsupported Request And further: 'David did something like this [1], but just for Root Ports. That looks wrong to me because sec 6.21.3 says we should not have PTM enabled in an Upstream Port (i.e., in a downstream device like 08:00.0) unless it is already enabled in the Downstream Port (i.e., in the Root Port 00:1d.0).' So also disable upstream port PTM to make the PCI driver conform to the spec and solve the issue. [1] https://lore.kernel.org/all/20220408153159.106741-1-kai.heng.feng@canonical.com/ [2] https://lore.kernel.org/all/20220422222433.GA1464120@bhelgaas/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216210 Suggested-by: Bjorn Helgaas Cc: David E. Box Cc: Sathyanarayanan Kuppuswamy Signed-off-by: Kai-Heng Feng Reviewed-by: Mika Westerberg Tested-by: Kai-Heng Feng --- drivers/pci/pci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index cfaf40a540a82..8ba8a0e12946e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2717,7 +2717,8 @@ int pci_prepare_to_sleep(struct pci_dev *dev) * port to enter a lower-power PM state and the SoC to reach a * lower-power idle state as a whole. */ - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM) pci_disable_ptm(dev); pci_enable_wake(dev, target_state, wakeup); @@ -2775,7 +2776,8 @@ int pci_finish_runtime_suspend(struct pci_dev *dev) * port to enter a lower-power PM state and the SoC to reach a * lower-power idle state as a whole. */ - if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) + if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || + pci_pcie_type(dev) == PCI_EXP_TYPE_UPSTREAM) pci_disable_ptm(dev); __pci_enable_wake(dev, target_state, pci_dev_run_wake(dev));