From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:52940 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752117Ab3BUGxU (ORCPT ); Thu, 21 Feb 2013 01:53:20 -0500 Message-ID: <5125C45A.5020208@suse.de> Date: Thu, 21 Feb 2013 07:53:14 +0100 From: Hannes Reinecke MIME-Version: 1.0 To: Yinghai Lu Cc: Bjorn Helgaas , linux-kernel@vger.kernel.org, Frederik Himpe , Oliver Neukum , David Haerdeman , linux-usb@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] pci: do not try to assign irq 255 References: <1361182193-31894-1-git-send-email-hare@suse.de> <5124820D.2080900@suse.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 02/20/2013 05:57 PM, Yinghai Lu wrote: > On Tue, Feb 19, 2013 at 11:58 PM, Hannes Reinecke wrote: >>> >> Apparently this device is meant to use MSI _only_ so the BIOS developer >> didn't feel the need to assign an INTx here. >> >> According to PCI-3.0, section 6.8 (Message Signalled Interrupts): >>> It is recommended that devices implement interrupt pins to >>> provide compatibility in systems that do not support MSI >>> (devices default to interrupt pins). However, it is expected >>> that the need for interrupt pins will diminish over time. >>> Devices that do not support interrupt pins due to pin >>> constraints (rely on polling for device service) may implement >>> messages to increase performance without adding additional pins. > >>> Therefore, system configuration software must not assume that a >>> message capable device has an interrupt pin. >> >> Which sounds to me as if the implementation is valid... > > it seems you mess pin with interrupt line. > > current code: > unsigned char irq; > > pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq); > dev->pin = irq; > if (irq) > pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq); > dev->irq = irq; > > so if the device does not have interrupt pin implemented, pin should be zero. > and pin and irq in dev should > be all 0. > But the device _has_ an interrupt pin implemented. The whole point here is that the interrupt line is _NOT_ zero. 00:14.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller [8086:1e31] (rev 04) (prog-if 30 [XHCI]) Subsystem: Hewlett-Packard Company Device [103c:179b] Control: I/O- Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- SERR- irq is not valid, despite it being not set to zero. An alternative fix would be this: diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c index 68a921d..4a480cb 100644 --- a/drivers/acpi/pci_irq.c +++ b/drivers/acpi/pci_irq.c @@ -469,6 +469,7 @@ int acpi_pci_irq_enable(struct pci_dev *dev) } else { dev_warn(&dev->dev, "PCI INT %c: no GSI\n", pin_name(pin)); + dev->irq = 0; } return 0; } Which probably is a better solution, as here ->irq is _definitely_ not valid, so we should reset it to '0' to avoid confusion on upper layers. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)