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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT 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 2D543C10F05 for ; Wed, 20 Mar 2019 13:46:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFF3C2184E for ; Wed, 20 Mar 2019 13:46:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553089596; bh=80pi8CDhxhnAicATU26JM+WFWXonPnHkyJuvgaQVVOs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ZYVZuPkrYf+aEbXhZSoK2zf98aN5D8H9s0Zuf6lQEdsBM1xaBmOupOe92Twyj27YT JNkwgjTgFtnD1w4X0o4TcU9nD+kgAxVXR8RPyp1fP1gKZyHmyXchMMi/VNpg5IoAtf o2+ay5HAh14oXiRZ3ydP1yNf1o6K4NDiHDboYG3k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727537AbfCTNqf (ORCPT ); Wed, 20 Mar 2019 09:46:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:33464 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726065AbfCTNqf (ORCPT ); Wed, 20 Mar 2019 09:46:35 -0400 Received: from localhost (173-28-64-202.client.mchsi.com [173.28.64.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 27DA32184D; Wed, 20 Mar 2019 13:46:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553089594; bh=80pi8CDhxhnAicATU26JM+WFWXonPnHkyJuvgaQVVOs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=xd0wdsesv8JcbO6/LYsIh4yBobMUD8nwdXd+/btzwnKHuxCNazvISQESKYZTqgtwk yR4pDL7hsov8+n8ahzxrr+j1xY7qSL3iMx98/8bszqaslloN7LBGvzDY2JUUBZUjbY AcdXj3DtdCNbeMQfPjhLeq/QYZIkQH8+Hx49/n+c= Date: Wed, 20 Mar 2019 08:46:32 -0500 From: Bjorn Helgaas To: Alexandru Gagniuc Cc: austin_bolen@dell.com, alex_gagniuc@dellteam.com, keith.busch@intel.com, Shyam_Iyer@Dell.com, lukas@wunner.de, okaya@kernel.org, torvalds@linux-foundation.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI/LINK: bw_notification: Do not leave interrupt handler NULL Message-ID: <20190320134632.GA251185@google.com> References: <20190319011214.7847-1-mr.nuke.me@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190319011214.7847-1-mr.nuke.me@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi Alexandru, On Mon, Mar 18, 2019 at 08:12:04PM -0500, Alexandru Gagniuc wrote: > A threaded IRQ with a NULL handler does not work with level-triggered > interrupts. request_threaded_irq() will return an error: > > genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq 16 > pcie_bw_notification: probe of 0000:00:1b.0:pcie010 failed with error -22 > > For level interrupts we need to silence the interrupt before exiting > the IRQ handler, so just clear the PCI_EXP_LNKSTA_LBMS bit there. > > Reported-by: Linus Torvalds > Signed-off-by: Alexandru Gagniuc What's your thought regarding Lukas' comment? If you do repost this, please add a Fixes: tag to help connect this with the initial commit. If not, I can add the tag myself. > --- > > OOPS! I'm sorry for the noise. Here's the fix. > > I was able to test this on edge-triggered interrupts. None of my > machines have PCIe ports that use level-triggered interrupts. This > might not be too straightforward to test without a hardware yanker, > but if there's a way to force a specific interrupt to be level > triggered, I could do the testing on my end. > > drivers/pci/pcie/bw_notification.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c > index d2eae3b7cc0f..001d6253ad48 100644 > --- a/drivers/pci/pcie/bw_notification.c > +++ b/drivers/pci/pcie/bw_notification.c > @@ -44,11 +44,10 @@ static void pcie_disable_link_bandwidth_notification(struct pci_dev *dev) > pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl); > } > > -static irqreturn_t pcie_bw_notification_handler(int irq, void *context) > +static irqreturn_t pcie_bw_notification_irq(int irq, void *context) > { > struct pcie_device *srv = context; > struct pci_dev *port = srv->port; > - struct pci_dev *dev; > u16 link_status, events; > int ret; > > @@ -58,6 +57,17 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context) > if (ret != PCIBIOS_SUCCESSFUL || !events) > return IRQ_NONE; > > + pcie_capability_write_word(port, PCI_EXP_LNKSTA, events); > + return IRQ_WAKE_THREAD; > +} > + > +static irqreturn_t pcie_bw_notification_handler(int irq, void *context) > +{ > + struct pcie_device *srv = context; > + struct pci_dev *port = srv->port; > + struct pci_dev *dev; > + u16 link_status; > + > /* > * Print status from downstream devices, not this root port or > * downstream switch port. > @@ -67,8 +77,8 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context) > __pcie_print_link_status(dev, false); > up_read(&pci_bus_sem); > > + pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status); > pcie_update_link_speed(port->subordinate, link_status); > - pcie_capability_write_word(port, PCI_EXP_LNKSTA, events); > return IRQ_HANDLED; > } > > @@ -80,7 +90,8 @@ static int pcie_bandwidth_notification_probe(struct pcie_device *srv) > if (!pcie_link_bandwidth_notification_supported(srv->port)) > return -ENODEV; > > - ret = request_threaded_irq(srv->irq, NULL, pcie_bw_notification_handler, > + ret = request_threaded_irq(srv->irq, pcie_bw_notification_irq, > + pcie_bw_notification_handler, > IRQF_SHARED, "PCIe BW notif", srv); > if (ret) > return ret; > -- > 2.19.2 >