From patchwork Sun Aug 25 13:47:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 1976497 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2604:1380:45d1:ec00::1; helo=ny.mirrors.kernel.org; envelope-from=linux-pci+bounces-12173-incoming=patchwork.ozlabs.org@vger.kernel.org; receiver=patchwork.ozlabs.org) Received: from ny.mirrors.kernel.org (ny.mirrors.kernel.org [IPv6:2604:1380:45d1:ec00::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4WsFVl2Jcqz1ygH for ; Sun, 25 Aug 2024 23:47:43 +1000 (AEST) Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id B40EB1C20C14 for ; Sun, 25 Aug 2024 13:47:40 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D082E1537A4; Sun, 25 Aug 2024 13:47:33 +0000 (UTC) X-Original-To: linux-pci@vger.kernel.org Received: from angie.orcam.me.uk (angie.orcam.me.uk [78.133.224.34]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2896C13F458; Sun, 25 Aug 2024 13:47:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.133.224.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593653; cv=none; b=t/L/0aMMMsPlznpiUca8jy9txAfDmtzoTnOZPmMed3/mahzecglI1seHnLH7n9GEM9dv9jM9oo2nHfrSnM4R1Tz0DRqi+l+5x8niBcONfjjpVlWjdrJsSk3pv4YiANTaAfWhG0krIKxlk+VGow/XidLh1e28rmuzrfu3RpCnz7s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593653; c=relaxed/simple; bh=mYwbke1zdDrcretydAP2RY06U0kSmkFoCcERsWUTMVo=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=ZtuqCrsw60WDujl1VGgx6rCfs8FDkPxBGzFhNzpdl8+gFzzjqGtAX1NiSNTDcyYZB43tZ5z8yhoBy+4yY/j8Ek68xDXuNqNaHxXNEpGRDGwq5nlum0exE2vE7FnerT6Sjmh9K+6dkeDflo//lXksJOeeiFi+UCsybC636bqdD28= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk; spf=none smtp.mailfrom=orcam.me.uk; arc=none smtp.client-ip=78.133.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=orcam.me.uk Received: by angie.orcam.me.uk (Postfix, from userid 500) id 667A892009C; Sun, 25 Aug 2024 15:47:29 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 6475D92009B; Sun, 25 Aug 2024 14:47:29 +0100 (BST) Date: Sun, 25 Aug 2024 14:47:29 +0100 (BST) From: "Maciej W. Rozycki" To: =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Matthew W Carlis , Bjorn Helgaas cc: Mika Westerberg , Oliver O'Halloran , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/4] PCI: Clear the LBMS bit after a link retrain In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The LBMS bit, where implemented, is set by hardware either in response to the completion of retraining caused by writing 1 to the Retrain Link bit or whenever hardware has changed the link speed or width in attempt to correct unreliable link operation. It is never cleared by hardware other than by software writing 1 to the bit position in the Link Status register and we never do such a write. We currently have two places, namely `apply_bad_link_workaround' and `pcie_failed_link_retrain' in drivers/pci/controller/dwc/pcie-tegra194.c and drivers/pci/quirks.c respectively where we check the state of the LBMS bit and neither is interested in the state of the bit resulting from the completion of retraining, both check for a link fault. And in particular `pcie_failed_link_retrain' causes issues consequently, by trying to retrain a link where there's no downstream device anymore and the state of 1 in the LBMS bit has been retained from when there was a device downstream that has since been removed. Clear the LBMS bit then at the conclusion of `pcie_retrain_link', so that we have a single place that controls it and that our code can track link speed or width changes resulting from unreliable link operation. Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures") Reported-by: Matthew W Carlis Link: https://lore.kernel.org/r/20240806000659.30859-1-mattc@purestorage.com/ Link: https://lore.kernel.org/r/20240722193407.23255-1-mattc@purestorage.com/ Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v6.5+ --- No change from v2. New change in v2. --- drivers/pci/pci.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) linux-pcie-retrain-link-lbms-clear.diff Index: linux-macro/drivers/pci/pci.c =================================================================== --- linux-macro.orig/drivers/pci/pci.c +++ linux-macro/drivers/pci/pci.c @@ -4718,7 +4718,15 @@ int pcie_retrain_link(struct pci_dev *pd pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_RL); } - return pcie_wait_for_link_status(pdev, use_lt, !use_lt); + rc = pcie_wait_for_link_status(pdev, use_lt, !use_lt); + + /* + * Clear LBMS after a manual retrain so that the bit can be used + * to track link speed or width changes made by hardware itself + * in attempt to correct unreliable link operation. + */ + pcie_capability_write_word(pdev, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS); + return rc; } /** From patchwork Sun Aug 25 13:47:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 1976498 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2604:1380:45d1:ec00::1; helo=ny.mirrors.kernel.org; envelope-from=linux-pci+bounces-12174-incoming=patchwork.ozlabs.org@vger.kernel.org; receiver=patchwork.ozlabs.org) Received: from ny.mirrors.kernel.org (ny.mirrors.kernel.org [IPv6:2604:1380:45d1:ec00::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4WsFVy46Pxz1ygH for ; Sun, 25 Aug 2024 23:47:54 +1000 (AEST) Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id A9D6A1C20C24 for ; Sun, 25 Aug 2024 13:47:52 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A3C9515573C; Sun, 25 Aug 2024 13:47:37 +0000 (UTC) X-Original-To: linux-pci@vger.kernel.org Received: from angie.orcam.me.uk (angie.orcam.me.uk [78.133.224.34]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 531DB156F5D; Sun, 25 Aug 2024 13:47:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.133.224.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593657; cv=none; b=VkIxFPMcoejQG+2PRwu9j0WVPSkLeh/uUekIvRMFpbyVZdXL3XRoJvJEm3RyifOpZWVSssYnaCm1nwnuQgH4ENy534Vs3OYloUNpcEyL9i8+tP1WcJUBOoYzspGcv0Kp3qoRMYhVc2H/d75GPVgt31Ob9oIsDPlh4j7hqSDM6Xg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593657; c=relaxed/simple; bh=43V8fSOAt4n23KEKHNBs62n3AClRL2dxS4yXIf/NKUk=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=DKvxv5IHgqOUAWcIDpgWa6RUEElERJTptXnHlvkGqvFxwbsDQwNtc9v8KrvlqdW+Q5rVlzjevgGNspSN5uJLTANNjdA8/s750iqdcyo4lqULP9EqBPMrmOoPzgHTHBvCZaFa7R4+QEaaLy+7N9hDXKsYB1Pl9AgkqXoKJs+nzuM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk; spf=none smtp.mailfrom=orcam.me.uk; arc=none smtp.client-ip=78.133.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=orcam.me.uk Received: by angie.orcam.me.uk (Postfix, from userid 500) id 317FC92009C; Sun, 25 Aug 2024 15:47:34 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 2E05D92009B; Sun, 25 Aug 2024 14:47:34 +0100 (BST) Date: Sun, 25 Aug 2024 14:47:34 +0100 (BST) From: "Maciej W. Rozycki" To: =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Matthew W Carlis , Bjorn Helgaas cc: Mika Westerberg , Oliver O'Halloran , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 2/4] PCI: Revert to the original speed after PCIe failed link retraining In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 When `pcie_failed_link_retrain' has failed to retrain the link by hand it leaves the link speed restricted to 2.5GT/s, which will then affect any device that has been plugged in later on, which may not suffer from the problem that caused the speed restriction to have been attempted. Consequently such a downstream device will suffer from an unnecessary communication throughput limitation and therefore performance loss. Remove the speed restriction then and revert the Link Control 2 register to its original state if link retraining with the speed restriction in place has failed. Retrain the link again afterwards so as to remove any residual state, waiting on LT rather than DLLLA to avoid an excessive delay and ignoring the result as this training is supposed to fail anyway. Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures") Reported-by: Matthew W Carlis Link: https://lore.kernel.org/r/20240806000659.30859-1-mattc@purestorage.com/ Link: https://lore.kernel.org/r/20240722193407.23255-1-mattc@purestorage.com/ Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v6.5+ Reviewed-by: Ilpo Järvinen --- Changes from v2: - Wait on LT rather than DLLLA with clean-up retraining with the speed restriction lifted, so as to avoid an excessive delay as it's supposed to fail anyway. New change in v2. --- drivers/pci/quirks.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) linux-pcie-failed-link-retrain-fail-unclamp.diff Index: linux-macro/drivers/pci/quirks.c =================================================================== --- linux-macro.orig/drivers/pci/quirks.c +++ linux-macro/drivers/pci/quirks.c @@ -66,7 +66,7 @@ * apply this erratum workaround to any downstream ports as long as they * support Link Active reporting and have the Link Control 2 register. * Restrict the speed to 2.5GT/s then with the Target Link Speed field, - * request a retrain and wait 200ms for the data link to go up. + * request a retrain and check the result. * * If this turns out successful and we know by the Vendor:Device ID it is * safe to do so, then lift the restriction, letting the devices negotiate @@ -74,6 +74,10 @@ * firmware may have already arranged and lift it with ports that already * report their data link being up. * + * Otherwise revert the speed to the original setting and request a retrain + * again to remove any residual state, ignoring the result as it's supposed + * to fail anyway. + * * Return TRUE if the link has been successfully retrained, otherwise FALSE. */ bool pcie_failed_link_retrain(struct pci_dev *dev) @@ -92,6 +96,8 @@ bool pcie_failed_link_retrain(struct pci pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); if ((lnksta & (PCI_EXP_LNKSTA_LBMS | PCI_EXP_LNKSTA_DLLLA)) == PCI_EXP_LNKSTA_LBMS) { + u16 oldlnkctl2 = lnkctl2; + pci_info(dev, "broken device, retraining non-functional downstream link at 2.5GT/s\n"); lnkctl2 &= ~PCI_EXP_LNKCTL2_TLS; @@ -100,6 +106,9 @@ bool pcie_failed_link_retrain(struct pci if (pcie_retrain_link(dev, false)) { pci_info(dev, "retraining failed\n"); + pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, + oldlnkctl2); + pcie_retrain_link(dev, true); return false; } From patchwork Sun Aug 25 13:47:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 1976499 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2604:1380:45d1:ec00::1; helo=ny.mirrors.kernel.org; envelope-from=linux-pci+bounces-12175-incoming=patchwork.ozlabs.org@vger.kernel.org; receiver=patchwork.ozlabs.org) Received: from ny.mirrors.kernel.org (ny.mirrors.kernel.org [IPv6:2604:1380:45d1:ec00::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4WsFWC2NGTz1ygH for ; Sun, 25 Aug 2024 23:48:07 +1000 (AEST) Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ny.mirrors.kernel.org (Postfix) with ESMTPS id 534071C20D41 for ; Sun, 25 Aug 2024 13:48:05 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 9E17D1537A4; Sun, 25 Aug 2024 13:47:43 +0000 (UTC) X-Original-To: linux-pci@vger.kernel.org Received: from angie.orcam.me.uk (angie.orcam.me.uk [78.133.224.34]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 55507155C93; Sun, 25 Aug 2024 13:47:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.133.224.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593663; cv=none; b=MnYWTaxzMavp7VyBBo+JO0fQOln8HvQktf536EEindU/3ebQJAHtp6LKLQFJAZg9UZsccaGZAx0hSQsqYxh4mxsCWCDQfXthENYISND2x+pKAEIDcyIVjHU5GKFTCgmQSwVJ1zV0bk99ROEdh4vaHygAkM/LztPeloapJTlEZ2o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593663; c=relaxed/simple; bh=HXenWO0mvS6SJdnD9Sh0kToK3+6VoC+91twZpxSvFHg=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=YdouFKfSfnJSok5w2vmirg0Qadh80V4n9hD1gOFNsuYab/AWNA6xsQe15CwgIucg7SjU1Hog3aLn7QZGuj4Gv3ooF6qGYejpEBuhEUs9aPyjCsI0D4fzIgriPoZApQCjUj87FhfClirfRlAErjc9LMYB31WO07nolL/MREu97pw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk; spf=none smtp.mailfrom=orcam.me.uk; arc=none smtp.client-ip=78.133.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=orcam.me.uk Received: by angie.orcam.me.uk (Postfix, from userid 500) id F365192009D; Sun, 25 Aug 2024 15:47:39 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id ED6CB92009B; Sun, 25 Aug 2024 14:47:39 +0100 (BST) Date: Sun, 25 Aug 2024 14:47:39 +0100 (BST) From: "Maciej W. Rozycki" To: =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Matthew W Carlis , Bjorn Helgaas cc: Mika Westerberg , Oliver O'Halloran , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 3/4] PCI: Correct error reporting with PCIe failed link retraining In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Only return successful completion status from `pcie_failed_link_retrain' if retraining has actually been done, preventing excessive delays from being triggered at call sites in a hope that communication will finally be established with the downstream device where in fact nothing has been done about the link in question that would justify such a hope. Fixes: a89c82249c37 ("PCI: Work around PCIe link training failures") Reported-by: Ilpo Järvinen Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@linux.intel.com/ Signed-off-by: Maciej W. Rozycki Reviewed-by: Ilpo Järvinen Cc: stable@vger.kernel.org # v6.5+ --- No changes from v2. Changes from v1 (superseding 1/2): - Regenerate on top of 2/4. - Reword the comment update for clarity. - Go back to returning explicit FALSE rather than `ret' where it is known that we failed. --- drivers/pci/quirks.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) linux-pcie-failed-link-retrain-status-fix.diff Index: linux-macro/drivers/pci/quirks.c =================================================================== --- linux-macro.orig/drivers/pci/quirks.c +++ linux-macro/drivers/pci/quirks.c @@ -78,7 +78,8 @@ * again to remove any residual state, ignoring the result as it's supposed * to fail anyway. * - * Return TRUE if the link has been successfully retrained, otherwise FALSE. + * Return TRUE if the link has been successfully retrained. Return FALSE + * if retraining was not needed or we attempted a retrain and it failed. */ bool pcie_failed_link_retrain(struct pci_dev *dev) { @@ -87,6 +88,7 @@ bool pcie_failed_link_retrain(struct pci {} }; u16 lnksta, lnkctl2; + bool ret = false; if (!pci_is_pcie(dev) || !pcie_downstream_port(dev) || !pcie_cap_has_lnkctl2(dev) || !dev->link_active_reporting) @@ -104,7 +106,8 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |= PCI_EXP_LNKCTL2_TLS_2_5GT; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); - if (pcie_retrain_link(dev, false)) { + ret = pcie_retrain_link(dev, false) == 0; + if (!ret) { pci_info(dev, "retraining failed\n"); pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, oldlnkctl2); @@ -126,13 +129,14 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |= lnkcap & PCI_EXP_LNKCAP_SLS; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); - if (pcie_retrain_link(dev, false)) { + ret = pcie_retrain_link(dev, false) == 0; + if (!ret) { pci_info(dev, "retraining failed\n"); return false; } } - return true; + return ret; } static ktime_t fixup_debug_start(struct pci_dev *dev, From patchwork Sun Aug 25 13:47:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 1976500 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2604:1380:45e3:2400::1; helo=sv.mirrors.kernel.org; envelope-from=linux-pci+bounces-12176-incoming=patchwork.ozlabs.org@vger.kernel.org; receiver=patchwork.ozlabs.org) Received: from sv.mirrors.kernel.org (sv.mirrors.kernel.org [IPv6:2604:1380:45e3:2400::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4WsFWQ4bJSz1ygH for ; Sun, 25 Aug 2024 23:48:18 +1000 (AEST) Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sv.mirrors.kernel.org (Postfix) with ESMTPS id 3F7FD2820BA for ; Sun, 25 Aug 2024 13:48:17 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 05B8816C69F; Sun, 25 Aug 2024 13:47:48 +0000 (UTC) X-Original-To: linux-pci@vger.kernel.org Received: from angie.orcam.me.uk (angie.orcam.me.uk [78.133.224.34]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2830E155727; Sun, 25 Aug 2024 13:47:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.133.224.34 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593667; cv=none; b=bjQzglQ1SzuS/C1GMz0Ivpza94GQ64S9JKXTfvxbOFlmH+cB9FqxnRsvv/NC0mQnwXUIyl0R0A0crYsLvKPCx5xC2t2IWGKwgxiRoOh9NT+AZ+XZ5FENuUtK4aAePraGu/UKZoWkDG+DcHMguasx8f/votazN/XhHtmfK8yW6uY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724593667; c=relaxed/simple; bh=bIzM3uWDDV2Xj7QItaFOLiOTUVZ6W104VSZEtoQ9mkw=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type; b=g49h+BJcMyqlXuveIk1xMS1Ol1pQLemiPiBUObG5U8a9NbC2fgXgD4AX1fZMM1TRBhtOVOPrNa1KmYKIbe4kdAvKFiC2Gw3iKa8hnQjcfW6wdkDEhA/PGtSNKtQJK4lti5sJaMs0K5M5EqnA81pVkoxN2HG/APnEKqK3JhpwNMk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk; spf=none smtp.mailfrom=orcam.me.uk; arc=none smtp.client-ip=78.133.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=orcam.me.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=orcam.me.uk Received: by angie.orcam.me.uk (Postfix, from userid 500) id 2453892009D; Sun, 25 Aug 2024 15:47:45 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id 1F1D792009B; Sun, 25 Aug 2024 14:47:45 +0100 (BST) Date: Sun, 25 Aug 2024 14:47:45 +0100 (BST) From: "Maciej W. Rozycki" To: =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Matthew W Carlis , Bjorn Helgaas cc: Mika Westerberg , Oliver O'Halloran , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 4/4] PCI: Use an error code with PCIe failed link retraining In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Given how the call place in `pcie_wait_for_link_delay' got structured now, and that `pcie_retrain_link' returns a potentially useful error code, convert `pcie_failed_link_retrain' to return an error code rather than a boolean status, fixing handling at the call site mentioned. Update the other call site accordingly. Fixes: 1abb47390350 ("Merge branch 'pci/enumeration'") Reported-by: Ilpo Järvinen Link: https://lore.kernel.org/r/aa2d1c4e-9961-d54a-00c7-ddf8e858a9b0@linux.intel.com/ Signed-off-by: Maciej W. Rozycki Reviewed-by: Ilpo Järvinen Cc: stable@vger.kernel.org # v6.5+ --- Changes from v2: - Regenerate following changes to 2/4, no functional change. Changes from v1 (superseding 2/2): - Regenerate following changes to 3/4, no functional change. --- drivers/pci/pci.c | 2 +- drivers/pci/pci.h | 6 +++--- drivers/pci/quirks.c | 20 ++++++++++---------- 3 files changed, 14 insertions(+), 14 deletions(-) linux-pcie-failed-link-retrain-status-int.diff Index: linux-macro/drivers/pci/pci.c =================================================================== --- linux-macro.orig/drivers/pci/pci.c +++ linux-macro/drivers/pci/pci.c @@ -1324,7 +1324,7 @@ static int pci_dev_wait(struct pci_dev * if (delay > PCI_RESET_WAIT) { if (retrain) { retrain = false; - if (pcie_failed_link_retrain(bridge)) { + if (pcie_failed_link_retrain(bridge) == 0) { delay = 1; continue; } Index: linux-macro/drivers/pci/pci.h =================================================================== --- linux-macro.orig/drivers/pci/pci.h +++ linux-macro/drivers/pci/pci.h @@ -606,7 +606,7 @@ void pci_acs_init(struct pci_dev *dev); int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags); int pci_dev_specific_enable_acs(struct pci_dev *dev); int pci_dev_specific_disable_acs_redir(struct pci_dev *dev); -bool pcie_failed_link_retrain(struct pci_dev *dev); +int pcie_failed_link_retrain(struct pci_dev *dev); #else static inline int pci_dev_specific_acs_enabled(struct pci_dev *dev, u16 acs_flags) @@ -621,9 +621,9 @@ static inline int pci_dev_specific_disab { return -ENOTTY; } -static inline bool pcie_failed_link_retrain(struct pci_dev *dev) +static inline int pcie_failed_link_retrain(struct pci_dev *dev) { - return false; + return -ENOTTY; } #endif Index: linux-macro/drivers/pci/quirks.c =================================================================== --- linux-macro.orig/drivers/pci/quirks.c +++ linux-macro/drivers/pci/quirks.c @@ -78,21 +78,21 @@ * again to remove any residual state, ignoring the result as it's supposed * to fail anyway. * - * Return TRUE if the link has been successfully retrained. Return FALSE + * Return 0 if the link has been successfully retrained. Return an error * if retraining was not needed or we attempted a retrain and it failed. */ -bool pcie_failed_link_retrain(struct pci_dev *dev) +int pcie_failed_link_retrain(struct pci_dev *dev) { static const struct pci_device_id ids[] = { { PCI_VDEVICE(ASMEDIA, 0x2824) }, /* ASMedia ASM2824 */ {} }; u16 lnksta, lnkctl2; - bool ret = false; + int ret = -ENOTTY; if (!pci_is_pcie(dev) || !pcie_downstream_port(dev) || !pcie_cap_has_lnkctl2(dev) || !dev->link_active_reporting) - return false; + return ret; pcie_capability_read_word(dev, PCI_EXP_LNKCTL2, &lnkctl2); pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); @@ -106,13 +106,13 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |= PCI_EXP_LNKCTL2_TLS_2_5GT; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); - ret = pcie_retrain_link(dev, false) == 0; - if (!ret) { + ret = pcie_retrain_link(dev, false); + if (ret) { pci_info(dev, "retraining failed\n"); pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, oldlnkctl2); pcie_retrain_link(dev, true); - return false; + return ret; } pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta); @@ -129,10 +129,10 @@ bool pcie_failed_link_retrain(struct pci lnkctl2 |= lnkcap & PCI_EXP_LNKCAP_SLS; pcie_capability_write_word(dev, PCI_EXP_LNKCTL2, lnkctl2); - ret = pcie_retrain_link(dev, false) == 0; - if (!ret) { + ret = pcie_retrain_link(dev, false); + if (ret) { pci_info(dev, "retraining failed\n"); - return false; + return ret; } }