On 27/03/2017 19:09, Marc Zyngier wrote: > Here's what your system looks like: > > PCI-EP -------> MSI Controller ------> INTC > MSI IRQ > > A PCI MSI is always edge. No ifs, no buts. That's what it is, and nothing > else. Now, your MSI controller signals its output using a level interrupt, > since you need to whack it on the head so that it lowers its line. > > There is not a single trigger, because there is not a single interrupt. Hello Marc, I was hoping you or Thomas might help clear some confusion in my mind around IRQ domains (struct irq_domain). I have read https://www.kernel.org/doc/Documentation/IRQ-domain.txt IIUC, there should be one IRQ domain per IRQ controller. I have this MSI controller handling 256 interrupts, so I should have *one* domain for all possible MSIs. Yet the Altera driver registers *two* domains (msi_domain and inner_domain). Could I make everything work with a single IRQ domain? I'm confused by the sequence: irq_dom = irq_domain_create_linear(fwnode, MSI_COUNT, &msi_dom_ops, pcie); msi_dom = pci_msi_create_irq_domain(fwnode, &msi_domain_info, irq_dom); It seems I should be able to call only pci_msi_create_irq_domain... And the parent of the MSI controller is given in the DT. I'm not quite sure how I tell pci_msi_create_irq_domain how many MSIs it's supposed to manage. Nor how I pass my private struct. I will keep looking. Regards.
