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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 7325DC12002 for ; Fri, 16 Jul 2021 21:56:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51C79613F3 for ; Fri, 16 Jul 2021 21:56:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230490AbhGPV7o (ORCPT ); Fri, 16 Jul 2021 17:59:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:59954 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229951AbhGPV7o (ORCPT ); Fri, 16 Jul 2021 17:59:44 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9BE93613F1; Fri, 16 Jul 2021 21:56:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626472608; bh=tKOagru+qVjZu758/c2+PD/cp+FBJEYcEqv4iWhxaPM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=e2UqQdNW5pYCKTyKK8jAqDuZqpEirChvkwC599w+H6aOm9Qv8mu9vy48R51bYAr0j w3yCkdaLqpqIKUWJZK1HoYcHsFLWBHYpVXq3Zr7YoSVjTTwo+B9ifXHaXZaUobTqEW 3pQ1ggAuaoDtyEZ9t1wn0V64OH29cF8Futx8VmCFYYumKBx0Akm6BtmzcFwEOVAzHU CJ7+FKQqUIoYRikNq+AqZIpJWXxhg+nBu2vFOKKigN/Inalh9OK68cNBtnz4pU3y0L T9ND9WMdh4Bxd2t+Or2QLw+7vrlhS2p3NObkHye4pyt/7cnerVAG9umOO/P+Wf9xow H2VYyTbl/sWWA== Date: Fri, 16 Jul 2021 16:56:47 -0500 From: Bjorn Helgaas To: Stuart Hayes Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, Lukas Wunner Subject: Re: [PATCH v2] PCI/portdrv: Use link bandwidth notification capability bit Message-ID: <20210716215647.GA2146665@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210512213314.7778-1-stuart.w.hayes@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, May 13, 2021 at 03:03:14AM +0530, Stuart Hayes wrote: > The pcieport driver can fail to attach to a downstream port that doesn't > support bandwidth notification. This can happen when, in > pcie_port_device_register(), pci_init_service_irqs() tries (and fails) to > set up a bandwidth notification IRQ for a device that doesn't support it. I'm trying to figure out exactly how this fails. The only failure path in pcie_init_service_irqs() is when pci_alloc_irq_vectors(PCI_IRQ_LEGACY) fails, which I guess means the port's dev->irq was zero? And to even attempt legacy IRQs, either we had pcie_pme_no_msi() or pcie_port_enable_irq_vec() failed? > This patch changes get_port_device_capability() to look at the link > bandwidth notification capability bit in the link capabilities register of > the port, instead of assuming that all downstream ports have that > capability. I think this needs: Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification") because even though b4c7d2076b4e ("PCI/LINK: Remove bandwidth notification") removed *most* of e8303bb7a75c, it did not remove the code in get_port_device_capability() that you're fixing here. I can fix this up locally, no need to resend. I think the patch itself is fine, just trying to understand the commit log. > Signed-off-by: Stuart Hayes > Reviewed-by: Lukas Wunner > --- > > changes from v1: > - corrected spelling errors in commit message > - added Lukas' reviewed-by: > > --- > drivers/pci/pcie/portdrv_core.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c > index e1fed6649c41..3ee63968deaa 100644 > --- a/drivers/pci/pcie/portdrv_core.c > +++ b/drivers/pci/pcie/portdrv_core.c > @@ -257,8 +257,13 @@ static int get_port_device_capability(struct pci_dev *dev) > services |= PCIE_PORT_SERVICE_DPC; > > if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM || > - pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) > - services |= PCIE_PORT_SERVICE_BWNOTIF; > + pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) { > + u32 linkcap; > + > + pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap); > + if (linkcap & PCI_EXP_LNKCAP_LBNC) > + services |= PCIE_PORT_SERVICE_BWNOTIF; > + } > > return services; > } > -- > 2.27.0 >