[PATCH] arch/i386/kernel/pci/irq.c: Wrong message output

Greg KH
2005-03-04T22:17:22Z

ChangeSet 1.1998.11.14, 2005/02/08 12:22:53-08:00, Mark.Haigh@spirentcom.com

[PATCH] arch/i386/kernel/pci/irq.c: Wrong message output

The following has been reported in the wild for kernel 2.6.8-24:

PCI: Enabling device 0000:00:05.0 (0000 -> 0002)
PCI: No IRQ known for interrupt pin @ of device 0000:00:05.0. 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 == '@'.

The supplied patch should fix it. It also removes a redundant check for
a nonzero pin.

Signed-off-by: Mark F. Haigh <Mark.Haigh@spirentcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

arch/i386/pci/irq.c | 73 +++++++++++++++++++++++++---------------------------
1 files changed, 36 insertions(+), 37 deletions(-)

diff -Nru a/arch/i386/pci/irq.c b/arch/i386/pci/irq.c
--- a/arch/i386/pci/irq.c 2005-03-04 12:42:38 -08:00
+++ b/arch/i386/pci/irq.c 2005-03-04 12:42:38 -08:00
@@ -1031,56 +1031,55 @@

pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
if (pin && !pcibios_lookup_irq(dev, 1) && !dev->irq) {
- char *msg;
- msg = "";
+ char *msg = "";
+
+ pin--; /* interrupt pins are numbered starting from 1 */
+
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;
-
- 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 %s[%c] to get irq %d\n",
- pci_name(bridge), 'A' + pin, irq);
- dev = bridge;
- }
- dev = temp_dev;
- if (irq >= 0) {
+ 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 %s[%c] to get irq %d\n",
+ pci_name(bridge), 'A' + pin, irq);
+ dev = bridge;
+ }
+ dev = temp_dev;
+ if (irq >= 0) {
#ifdef CONFIG_PCI_MSI
- if (!platform_legacy_irq(irq))
- irq = IO_APIC_VECTOR(irq);
+ if (!platform_legacy_irq(irq))
+ irq = IO_APIC_VECTOR(irq);
#endif
- printk(KERN_INFO "PCI->APIC IRQ transform: %s[%c] -> IRQ %d\n",
- pci_name(dev), 'A' + pin, irq);
- dev->irq = irq;
- return 0;
- } else
- msg = " Probably buggy MP table.";
- }
+ printk(KERN_INFO "PCI->APIC IRQ transform: %s[%c] -> IRQ %d\n",
+ pci_name(dev), 'A' + pin, irq);
+ dev->irq = irq;
+ return 0;
+ } else
+ msg = " Probably buggy MP table.";
} else if (pci_probe & PCI_BIOS_IRQ_SCAN)
msg = "";
else
msg = " Please try using pci=biosirq.";
-
+
/* With IDE legacy devices the IRQ lookup failure is not a problem.. */
if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE && !(dev->class & 0x5))
return 0;
-
+
printk(KERN_WARNING "PCI: No IRQ known for interrupt pin %c of device %s.%s\n",
- 'A' + pin - 1, pci_name(dev), msg);
+ 'A' + pin, pci_name(dev), msg);
}
/* VIA bridges use interrupt line for apic/pci steering across
the V-Link */