Messages in this thread | | | Date | Mon, 15 Oct 2007 18:17:55 -0400 | From | Jeff Garzik <> | Subject | Re: MSI interrupts and disable_irq |
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Manfred Spraul wrote: > Jeff Garzik wrote: >> >> I think the scenario you outline is an illustration of the approach's >> fragility: disable_irq() is a heavy hammer that originated with INTx, >> and it relies on a chip-specific disable method (kernel/irq/manage.c) >> that practically guarantees behavior will vary across MSI/INTx/etc. >> > I checked the code: IRQ_DISABLE is implemented in software, i.e. > handle_level_irq() only calls handle_IRQ_event() [and then the nic irq > handler] if IRQ_DISABLE is not set. > OTHO: The last trace looks as if nv_do_nic_poll() is interrupted by an irq. > > Perhaps something corrupts dev->irq? The irq is requested with > request_irq(np->pci_dev->irq, handler, IRQF_SHARED, dev->name, dev) > and disabled with > disable_irq_lockdep(dev->irq); > > Someone around with a MSI capable board? The forcedeth driver does > dev->irq = pci_dev->irq > in nv_probe(), especially before pci_enable_msi(). > Does pci_enable_msi() change pci_dev->irq? Then we would disable the > wrong interrupt....
Remember, fundamentally MSI-X is a one-to-many relationship, when you consider a single PCI device might have multiple vectors.
Jeff
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