From patchwork Wed May 1 13:22:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 10925077 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9A21F1390 for ; Wed, 1 May 2019 13:28:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7F71D28D5D for ; Wed, 1 May 2019 13:28:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 735AB28E1A; Wed, 1 May 2019 13:28:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EA42928D5D for ; Wed, 1 May 2019 13:28:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726083AbfEAN2i (ORCPT ); Wed, 1 May 2019 09:28:38 -0400 Received: from mga01.intel.com ([192.55.52.88]:43245 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726010AbfEAN2i (ORCPT ); Wed, 1 May 2019 09:28:38 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 May 2019 06:28:37 -0700 X-ExtLoop1: 1 Received: from unknown (HELO localhost.lm.intel.com) ([10.232.112.69]) by orsmga002.jf.intel.com with ESMTP; 01 May 2019 06:28:37 -0700 From: Keith Busch To: --to=Bjorn Helgaas , linux-pci@vger.kernel.org Cc: Alex Williamson , Alexandru Gagniuc , Keith Busch Subject: [PATCH] PCI/LINK: Add Kconfig option (default off) Date: Wed, 1 May 2019 07:22:48 -0600 Message-Id: <20190501132248.26842-1-keith.busch@intel.com> X-Mailer: git-send-email 2.13.6 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification") added dmesg logging whenever a link changes speed or width to a state that is considered degraded. Unfortunately, it cannot differentiate signal integrity-related link changes from those intentionally initiated by an endpoint driver, including drivers that may live in userspace or VMs when making use of vfio-pci. Some GPU drivers actively manage the link state to save power, which generates a stream of messages like this: vfio-pci 0000:07:00.0: 32.000 Gb/s available PCIe bandwidth, limited by 2.5 GT/s x16 link at 0000:00:02.0 (capable of 64.000 Gb/s with 5 GT/s x16 link) Since we can't distinguish the intentional changes from the signal integrity issues, leave the reporting turned off by default. Add a Kconfig option to turn it on if desired. Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification") Signed-off-by: Keith Busch --- drivers/pci/pcie/Kconfig | 9 +++++++++ drivers/pci/pcie/Makefile | 2 +- drivers/pci/pcie/portdrv.h | 4 ++++ 3 files changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig index 5cbdbca904ac..7f480685df93 100644 --- a/drivers/pci/pcie/Kconfig +++ b/drivers/pci/pcie/Kconfig @@ -142,3 +142,12 @@ config PCIE_PTM This is only useful if you have devices that support PTM, but it is safe to enable even if you don't. + +config PCIE_BW + bool "PCI Express Bandwidth Change Notification" + default n + depends on PCIEPORTBUS + help + This enables PCI Express Bandwidth Change Notification. If + you know link width or rate changes occur only to correct + unreliable links, you may answer Y. diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile index f1d7bc1e5efa..efb9d2e71e9e 100644 --- a/drivers/pci/pcie/Makefile +++ b/drivers/pci/pcie/Makefile @@ -3,7 +3,6 @@ # Makefile for PCI Express features and port driver pcieportdrv-y := portdrv_core.o portdrv_pci.o err.o -pcieportdrv-y += bw_notification.o obj-$(CONFIG_PCIEPORTBUS) += pcieportdrv.o @@ -13,3 +12,4 @@ obj-$(CONFIG_PCIEAER_INJECT) += aer_inject.o obj-$(CONFIG_PCIE_PME) += pme.o obj-$(CONFIG_PCIE_DPC) += dpc.o obj-$(CONFIG_PCIE_PTM) += ptm.o +obj-$(CONFIG_PCIE_BW) += bw_notification.o diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h index 1d50dc58ac40..944827a8c7d3 100644 --- a/drivers/pci/pcie/portdrv.h +++ b/drivers/pci/pcie/portdrv.h @@ -49,7 +49,11 @@ int pcie_dpc_init(void); static inline int pcie_dpc_init(void) { return 0; } #endif +#ifdef CONFIG_PCIE_BW int pcie_bandwidth_notification_init(void); +#else +static inline int pcie_bandwidth_notification_init(void) { return 0; } +#endif /* Port Type */ #define PCIE_ANY_PORT (~0)