On Tue, Sep 10, 2024 at 09:50:02AM -0700, Tim Harvey wrote: > On Fri, Sep 6, 2024 at 12:58 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Fri, Sep 06, 2024 at 12:37:42PM -0700, Tim Harvey wrote: > > > ... > > > > > I have the hardware in hand now as well as the out-of-tree driver > > > that's being used. I can say there is nothing wrong here with legacy > > > PCI interrupt mapping, if I write a skeleton driver that uses > > > pci_resister_driver(struct pci_driver) its probe is called with an > > > interrupt and request_irq on that interrupt succeeds just fine. > > > > > > The issue here is with the vendor's out-of-tree driver which instead > > > is using pci_get_device() to scan the bus which returns a struct > > > pci_dev * that doesn't have an irq assigned (like what is described > > > in > > > https://www.kernel.org/doc/html/v5.5/PCI/pci.html#how-to-find-pci-devices-manually). > > > When using pci_get_device() when/how does pci_assign_irq() get > > > called to assign the irq to the device? > > > > Hmmm. pci_get_device() is strongly discouraged because it subverts > > the driver model (it skips the usual driver probe/claim model so it > > allows multiple drivers to operate the device simultaneously which can > > obviously cause conflicts), and it doesn't play well with hotplug > > (hotplug events automatically cause driver .probe() methods to be > > called, but users of pci_get_device() have to roll their own way of > > doing this). > > > > So I'm not aware of a documented/supported way to set up the INTx > > interrupts in the pci_get_device() case. > > Makes sense to me. Perhaps some changes to Documentation/PCI/pci.rst > could explain this. Yeah, that would be a good idea. > Thanks for the help here, glad to find there is nothing broken here. I > think there could have been some confusion by the user here because > they were used to x86 assigning irq's without using > pci_resister_driver() but they were also using a kernel param of > pci=routeirq which looks like its an x86 only temporary workaround > that may have made this work on that architecture. I wondered about "pci=routirq", but I lost the trail and couldn't figure out how that would lead to pci_assign_irq() or something functionally equivalent. Bjorn
