Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261488AbVBHGTt (ORCPT ); Tue, 8 Feb 2005 01:19:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261490AbVBHGTs (ORCPT ); Tue, 8 Feb 2005 01:19:48 -0500 Received: from 207-105-1-25.zarak.com ([207.105.1.25]:23610 "HELO iceberg.Adtech-Inc.COM") by vger.kernel.org with SMTP id S261488AbVBHGTU (ORCPT ); Tue, 8 Feb 2005 01:19:20 -0500 Message-ID: <42085997.4080005@spirentcom.com> Date: Mon, 07 Feb 2005 22:17:59 -0800 From: "Mark F. Haigh" User-Agent: Mozilla Thunderbird (X11/20041216) X-Accept-Language: en-us, en MIME-Version: 1.0 To: marcelo.tosatti@cyclades.com CC: "Mark F. Haigh" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.4.19-bk8] arch/i386/kernel/pci-irq.c: Wrong message output References: <42084219.80608@spirentcom.com> <42085448.4010000@spirentcom.com> In-Reply-To: <42085448.4010000@spirentcom.com> Content-Type: multipart/mixed; boundary="------------060008090806070105050307" X-OriginalArrivalTime: 08 Feb 2005 06:19:19.0817 (UTC) FILETIME=[1FBD7790:01C50DA6] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4938 Lines: 137 This is a multi-part message in MIME format. --------------060008090806070105050307 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Mark F. Haigh wrote: > > Apologies. Patch now -p1-able. > [Apologies yet again, now includes description] I'd submitted a patch earlier for this file, fixing a warning. When I looked at it further, I noticed it can output an incorrect warning message under certain circumstances. I've confirmed that this can and does happen in the wild: PCI: Enabling device 0000:00:0a.0 (0000 -> 0001) PCI: No IRQ known for interrupt pin @ of device 0000:00:0a.0. Probably buggy MP table. It should read "No IRQ known for interrupt pin A", but the 'pin' variable has already been decremented (from 1 to 0), so the line: printk(KERN_WARNING "PCI: No IRQ known for interrupt pin %c of device %s.%s\n", 'A' + pin - 1, dev->slot_name, msg); causes "pin @" to be output, because 'A' + 0 - 1 == '@'. This patch also fixes the original warning: pci-irq.c: In function `pcibios_enable_irq': pci-irq.c:1128: warning: 'msg' might be used uninitialized in this function Thanks, Mark Haigh Mark.Haigh@spirentcom.com Signed-off-by: Mark F. Haigh --------------060008090806070105050307 Content-Type: text/plain; name="pci-irq-patch2" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="pci-irq-patch2" --- linux-2.4.29-bk8/arch/i386/kernel/pci-irq.c.orig 2005-02-07 19:55:23.000000000 -0800 +++ linux-2.4.29-bk8/arch/i386/kernel/pci-irq.c 2005-02-07 20:13:38.000000000 -0800 @@ -1127,6 +1127,8 @@ if (pin && !pcibios_lookup_irq(dev, 1) && !dev->irq) { char *msg; + pin--; /* interrupt pins are numbered starting from 1 */ + /* With IDE legacy devices the IRQ lookup failure is not a problem.. */ if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE && !(dev->class & 0x5)) return; @@ -1134,42 +1136,39 @@ if (io_apic_assign_pci_irqs) { int irq; - if (pin) { - pin--; /* interrupt pins are numbered starting from 1 */ - irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin); - /* - * Busses behind bridges are typically not listed in the MP-table. - * In this case we have to look up the IRQ based on the parent bus, - * parent slot, and pin number. The SMP code detects such bridged - * busses itself so we should get into this branch reliably. - */ - temp_dev = dev; - while (irq < 0 && dev->bus->parent) { /* go back to the bridge */ - struct pci_dev * bridge = dev->bus->self; + irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin); + /* + * Busses behind bridges are typically not listed in the MP-table. + * In this case we have to look up the IRQ based on the parent bus, + * parent slot, and pin number. The SMP code detects such bridged + * busses itself so we should get into this branch reliably. + */ + temp_dev = dev; + while (irq < 0 && dev->bus->parent) { /* go back to the bridge */ + struct pci_dev * bridge = dev->bus->self; - pin = (pin + PCI_SLOT(dev->devfn)) % 4; - irq = IO_APIC_get_PCI_irq_vector(bridge->bus->number, - PCI_SLOT(bridge->devfn), pin); - if (irq >= 0) - printk(KERN_WARNING "PCI: using PPB(B%d,I%d,P%d) to get irq %d\n", - bridge->bus->number, PCI_SLOT(bridge->devfn), pin, irq); - dev = bridge; - } - dev = temp_dev; - if (irq >= 0) { - printk(KERN_INFO "PCI->APIC IRQ transform: (B%d,I%d,P%d) -> %d\n", - dev->bus->number, PCI_SLOT(dev->devfn), pin, irq); - dev->irq = irq; - return; - } else - msg = " Probably buggy MP table."; + pin = (pin + PCI_SLOT(dev->devfn)) % 4; + irq = IO_APIC_get_PCI_irq_vector(bridge->bus->number, + PCI_SLOT(bridge->devfn), pin); + if (irq >= 0) + printk(KERN_WARNING "PCI: using PPB(B%d,I%d,P%d) to get irq %d\n", + bridge->bus->number, PCI_SLOT(bridge->devfn), pin, irq); + dev = bridge; } + dev = temp_dev; + if (irq >= 0) { + printk(KERN_INFO "PCI->APIC IRQ transform: (B%d,I%d,P%d) -> %d\n", + dev->bus->number, PCI_SLOT(dev->devfn), pin, irq); + dev->irq = irq; + return; + } else + msg = " Probably buggy MP table."; } else if (pci_probe & PCI_BIOS_IRQ_SCAN) msg = ""; else msg = " Please try using pci=biosirq."; printk(KERN_WARNING "PCI: No IRQ known for interrupt pin %c of device %s.%s\n", - 'A' + pin - 1, dev->slot_name, msg); + 'A' + pin, dev->slot_name, msg); } /* VIA bridges use interrupt line for apic/pci steering across the V-Link */ --------------060008090806070105050307-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/