Hi, Sorry in taking so long to track this down. I just got motivated today.
I have a VIA SMP system and somewhere between 2.6.12-rc3 and 2.6.12 the USB mouse started moving around really slowly. Anyway, it turns out that the attached patch (against 2.6.13-rc3-git8) fixes the problem. Let me know if any info is needed or if you would like me to test a patch. This is a regression versus 2.6.11 so it would be good to have a fix in 2.6.13. Thanks, Nick -- SUSE Labs, Novell Inc.
Index: linux-2.6/arch/i386/pci/irq.c =================================================================== --- linux-2.6.orig/arch/i386/pci/irq.c 2005-07-28 19:03:48.000000000 +1000 +++ linux-2.6/arch/i386/pci/irq.c 2005-07-28 21:58:52.000000000 +1000 @@ -1132,6 +1132,7 @@ static int pirq_enable_irq(struct pci_de printk(KERN_WARNING "PCI: No IRQ known for interrupt pin %c of device %s.%s\n", 'A' + pin, pci_name(dev), msg); } + pci_write_config_byte(dev, PCI_INTERRUPT_LINE, dev->irq & 15); return 0; } Index: linux-2.6/drivers/pci/quirks.c =================================================================== --- linux-2.6.orig/drivers/pci/quirks.c 2005-07-28 21:41:56.000000000 +1000 +++ linux-2.6/drivers/pci/quirks.c 2005-07-28 21:59:35.000000000 +1000 @@ -499,6 +499,7 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_V */ static void quirk_via_irq(struct pci_dev *dev) { +#if 0 u8 irq, new_irq; new_irq = dev->irq & 0xf; @@ -509,6 +510,7 @@ static void quirk_via_irq(struct pci_dev udelay(15); /* unknown if delay really needed */ pci_write_config_byte(dev, PCI_INTERRUPT_LINE, new_irq); } +#endif } DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_VIA, PCI_ANY_ID, quirk_via_irq); Index: linux-2.6/drivers/acpi/pci_irq.c =================================================================== --- linux-2.6.orig/drivers/acpi/pci_irq.c 2005-07-28 19:04:00.000000000 +1000 +++ linux-2.6/drivers/acpi/pci_irq.c 2005-07-28 21:58:14.000000000 +1000 @@ -444,6 +444,8 @@ acpi_pci_irq_enable ( } } + pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq & 15); + dev->irq = acpi_register_gsi(irq, edge_level, active_high_low); printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",