On Fri, Jun 10, 2016 at 06:36:12PM -0500, Bjorn Helgaas wrote: > On Fri, Jun 10, 2016 at 09:55:17PM +0200, Tomasz Nowicki wrote: > > To enable PCI legacy IRQs on platforms booting with ACPI, arch code > > should include ACPI specific callbacks that parse and set-up the > > device IRQ number, equivalent to the DT boot path. Owing to the current > > ACPI core scan handlers implementation, ACPI PCI legacy IRQs bindings > > cannot be parsed at device add time, since that would trigger ACPI scan > > handlers ordering issues depending on how the ACPI tables are defined. > > Uh, OK :) I can't figure out exactly what the problem is here -- I > don't know where to look if I wanted to fix the scan handler ordering > issues, and I don't know how I could tell if it would ever be safe to > move this from driver probe-time back to device add-time. Right, the commit log could have been more informative. pcibios_add_device() was added in: commit d1e6dc91b532 ("arm64: Add architectural support for PCI") whose commit log does not specify why legacy IRQ parsing should be done at pcibios_add_device() either, so honestly we had to do with the information we have at hand. > I also notice that x86 and ia64 call acpi_pci_irq_enable() even later, > when the driver *enables* the device. Is there a reason you didn't do > it at the same time as x86 and ia64? This is another of those pcibios > hooks that really don't do anything arch-specific, so I can imagine > refactoring this somehow, someday. Yes, with [1], that was the goal, that stopped because [1] does not work on x86. Only DT platform(s) affected by this change are all platforms relying on drivers/pci/host/pci-xgene.c (others rely on pci_fixup_irqs() that should be removed too), if on those platforms probing IRQs at device enable time works ok I can update this patch (it can be done through [1] once we figure out what to do with it on x86) and move the IRQ set-up at pcibios_enable_device() time. @Duc: any feedback on this ? Thanks, Lorenzo [1] http://www.spinics.net/lists/linux-pci/msg45950.html > Did we have this conversation before? It seems vaguely familiar, so I > apologize if you already explained this once. > > > To solve this problem and consolidate FW PCI legacy IRQs parsing in > > one single pcibios callback (pending final removal), this patch moves > > DT PCI IRQ parsing to the pcibios_alloc_irq() callback (called by > > PCI core code at device probe time) and adds ACPI PCI legacy IRQs > > parsing to the same callback too, so that FW PCI legacy IRQs parsing > > is confined in one single arch callback that can be easily removed > > when code parsing PCI legacy IRQs is consolidated and moved to core > > PCI code. > > > > Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx> > > Suggested-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> > > --- > > arch/arm64/kernel/pci.c | 11 ++++++++--- > > 1 file changed, 8 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm64/kernel/pci.c b/arch/arm64/kernel/pci.c > > index d5d3d26..b3b8a2c 100644 > > --- a/arch/arm64/kernel/pci.c > > +++ b/arch/arm64/kernel/pci.c > > @@ -51,11 +51,16 @@ int pcibios_enable_device(struct pci_dev *dev, int mask) > > } > > > > /* > > - * Try to assign the IRQ number from DT when adding a new device > > + * Try to assign the IRQ number when probing a new device > > */ > > -int pcibios_add_device(struct pci_dev *dev) > > +int pcibios_alloc_irq(struct pci_dev *dev) > > { > > - dev->irq = of_irq_parse_and_map_pci(dev, 0, 0); > > + if (acpi_disabled) > > + dev->irq = of_irq_parse_and_map_pci(dev, 0, 0); > > +#ifdef CONFIG_ACPI > > + else > > + return acpi_pci_irq_enable(dev); > > +#endif > > > > return 0; > > } > > -- > > 1.9.1 > > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html