From: Takayoshi K. <t-...@bq...> - 2004-09-24 05:52:46
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From: Kenji Kaneshige <kan...@jp...> Subject: Re: [ACPI] [PATCH] PCI IRQ resource deallocation support [2/3] Date: Wed, 22 Sep 2004 10:24:40 +0900 > >> + * dev->irq is cleared by BIOS-assigned IRQ set during boot. > >> + */ > >> + pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq); > >> + if (irq) > >> + pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq); > >> + dev->irq = irq; > > > > Why do we need to fiddle with dev->irq? I think it should > > just be undefined after acpi_pci_irq_disable(). > > I had been considering what the "undefined dev->irq" was. > In fact, I had other ideas that was clearing it by zero or > -1 (0xffffffff). But I didn't know if we can use these values > as a undefined IRQ number. So I'm clearing it by the value > which was assigned by PCI core code (pci_read_irq()) before > acpi_pci_irq_enable() was called. I think it has little sense in restoring value from the configuration space to dev->irq or clearing it. If we do preventive programming, it may be worth trying to define some magic constant (e.g. PCI_UNDEFINED_IRQ) and panic/BUG when the irq is being enabled. Otherwise, leaving dev->irq as it is would be ok. --- Takayoshi Kochi <t-...@bq...> |