From patchwork Fri Sep 2 23:35:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bjorn Helgaas X-Patchwork-Id: 602716 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 4E714C54EE9 for ; Fri, 2 Sep 2022 23:36:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230251AbiIBXgA (ORCPT ); Fri, 2 Sep 2022 19:36:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41516 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230163AbiIBXf5 (ORCPT ); Fri, 2 Sep 2022 19:35:57 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABAD5DFB68; Fri, 2 Sep 2022 16:35:55 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AD673B82E08; Fri, 2 Sep 2022 23:35:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36D47C433C1; Fri, 2 Sep 2022 23:35:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1662161752; bh=499J1ALryCuJ+6HDm82sa2IWHYaV94fHkOG4KesRkw8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aJwTCl//9uW8H+Ad+QJqYtqtDT8D6QOK3j+1/Omo9e2MFDRnjYlPPNoojaoQ3BW4d bu7jxbi62CQgoH/Rs6NjryqDBTFtQd0Y3LYceBbraa8d/JIoDT1fVen/g+SD9D3GRd 0GLPqNfJMrcRfaXLiaBJzuHyrKbKcESJQc3CmAL0F1BMI/ySEmUwdk5m1kxt+SlYGu F/FElKjHODWUImh0gHD/ZQ1InJzvqqsi08j8HCWl7Sl9z4f2sgOZXf/RlrIEEbeaFO fIQ2eohmC+Y7gEBomwB4bvaaODW6PMC0UF1LyZdnTuCNkdNRvXF8RQpO8w4UjcevmP P+117PJEV7I5A== From: Bjorn Helgaas To: Kai-Heng Feng , Rajvi Jingar , "Rafael J . Wysocki" Cc: Koba Ko , Mika Westerberg , "David E . Box" , Sathyanarayanan Kuppuswamy , linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Helgaas Subject: [PATCH v2 3/3] PCI/PM: Always disable PTM for all devices during suspend Date: Fri, 2 Sep 2022 18:35:43 -0500 Message-Id: <20220902233543.390890-4-helgaas@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220902233543.390890-1-helgaas@kernel.org> References: <20220902233543.390890-1-helgaas@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Bjorn Helgaas We want to disable PTM on Root Ports because that allows some chips, e.g., Intel mobile chips since Coffee Lake, to enter a lower-power PM state. That means we also have to disable PTM on downstream devices. PCIe r6.0, sec 2.2.8, recommends that functions support generation of messages in non-D0 states, so we have to assume Switch Upstream Ports or Endpoints may send PTM Requests while in D1, D2, and D3hot. A PTM message received by a Downstream Port (including a Root Port) with PTM disabled must be treated as an Unsupported Request (sec 6.21.3). PTM was previously disabled only for Root Ports, and it was disabled in pci_prepare_to_sleep(), which is not called at all if a driver supports legacy PM or does its own state saving. Instead, disable PTM early in pci_pm_suspend() and pci_pm_runtime_suspend() so we do it in all cases. Previously PTM was disabled *after* saving device state, so the state restore on resume automatically re-enabled it. Since we now disable PTM *before* saving state, we must explicitly re-enable it. Here's a sample of errors that occur when PTM is disabled only on the Root Port. With this topology: 0000:00:1d.0 Root Port to [bus 08-71] 0000:08:00.0 Switch Upstream Port to [bus 09-71] Kai-Heng reported errors like this: 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 Decoding TLP header 0x34...... (0011 0100b) and 0x08000052: Fmt 001b 4 DW header, no data Type 1 0100b Msg (Local - Terminate at Receiver) Requester ID 0x0800 Bus 08 Devfn 00.0 Message Code 0x52 0101 0010b PTM Request The 00:1d.0 Root Port logged an Unsupported Request error when it received a PTM Request with Requester ID 08:00.0. Fixes: a697f072f5da ("PCI: Disable PTM during suspend to save power") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=215453 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216210 Based-on: https://lore.kernel.org/r/20220706123244.18056-1-kai.heng.feng@canonical.com Based-on-patch-by: Kai-Heng Feng Reported-by: Kai-Heng Feng Signed-off-by: Bjorn Helgaas --- drivers/pci/pci-driver.c | 14 ++++++++++++++ drivers/pci/pci.c | 20 -------------------- 2 files changed, 14 insertions(+), 20 deletions(-) diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 2815922ac525..115febaa7e0b 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -772,6 +772,12 @@ static int pci_pm_suspend(struct device *dev) struct pci_dev *pci_dev = to_pci_dev(dev); const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + /* + * Disabling PTM allows some systems, e.g., Intel mobile chips + * since Coffee Lake, to enter a lower-power PM state. + */ + pci_disable_ptm(pci_dev); + pci_dev->skip_bus_pm = false; if (pci_has_legacy_pm_support(pci_dev)) @@ -982,6 +988,9 @@ static int pci_pm_resume(struct device *dev) if (pci_dev->state_saved) pci_restore_standard_config(pci_dev); + if (pci_dev->ptm_enabled) + pci_enable_ptm(pci_dev, NULL); + if (pci_has_legacy_pm_support(pci_dev)) return pci_legacy_resume(dev); @@ -1269,6 +1278,8 @@ static int pci_pm_runtime_suspend(struct device *dev) pci_power_t prev = pci_dev->current_state; int error; + pci_disable_ptm(pci_dev); + /* * If pci_dev->driver is not set (unbound), we leave the device in D0, * but it may go to D3cold when the bridge above it runtime suspends. @@ -1331,6 +1342,9 @@ static int pci_pm_runtime_resume(struct device *dev) */ pci_pm_default_resume_early(pci_dev); + if (pci_dev->ptm_enabled) + pci_enable_ptm(pci_dev, NULL); + if (!pci_dev->driver) return 0; diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 95bc329e74c0..b0e2968c8cca 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2706,16 +2706,6 @@ int pci_prepare_to_sleep(struct pci_dev *dev) if (target_state == PCI_POWER_ERROR) return -EIO; - /* - * There are systems (for example, Intel mobile chips since Coffee - * Lake) where the power drawn while suspended can be significantly - * reduced by disabling PTM on PCIe root ports as this allows the - * 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) - pci_disable_ptm(dev); - pci_enable_wake(dev, target_state, wakeup); error = pci_set_power_state(dev, target_state); @@ -2764,16 +2754,6 @@ int pci_finish_runtime_suspend(struct pci_dev *dev) if (target_state == PCI_POWER_ERROR) return -EIO; - /* - * There are systems (for example, Intel mobile chips since Coffee - * Lake) where the power drawn while suspended can be significantly - * reduced by disabling PTM on PCIe root ports as this allows the - * 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) - pci_disable_ptm(dev); - __pci_enable_wake(dev, target_state, pci_dev_run_wake(dev)); error = pci_set_power_state(dev, target_state);