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[98.195.139.126]) by smtp.gmail.com with ESMTPSA id j18sm1722353otq.68.2019.03.18.18.12.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 18 Mar 2019 18:12:30 -0700 (PDT) From: Alexandru Gagniuc To: bhelgaas@google.com 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, Alexandru Gagniuc , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] PCI/LINK: bw_notification: Do not leave interrupt handler NULL Date: Mon, 18 Mar 2019 20:12:04 -0500 Message-Id: <20190319011214.7847-1-mr.nuke.me@gmail.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org 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 --- 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