pci_irqd_intx_xlate(9)

okay so bestie, this is pci_irqd_intx_xlate(9) from the Kernel API Manual, and it's literally the tiny translator that takes a PCI INTx value and turns it into an IRQ domain hwirq number 💅✨

🎀 NAME 🎀

pci_irqd_intx_xlate — Translate PCI INTx value to an IRQ domain hwirq.

✨ SYNOPSIS ✨

int pci_irqd_intx_xlate (struct irq_domain *d , struct device_node *node
, const u32 *intspec , unsigned int intsize , unsigned long *out_hwirq ,
unsigned int *out_type );

💖 ARGUMENTS 💖

Here's the cast, bestie — every single one matters:

• d — the INTx IRQ domain. That's the domain doing the INTx thing 💫
• node — the DT node for the device whose interrupt we're translating.
• intspec — the interrupt specifier data from the DT.
• intsize — the number of entries in intspec.
• out_hwirq — pointer at which to write the hwirq number.
• out_type — pointer at which to write the interrupt type.

🦋 DESCRIPTION 🦋

Okay so the actual glow-up is this: translate a PCI INTx interrupt number from device tree in the range 1-4, as stored in the standard PCI_INTERRUPT_PIN register, to a value in the range 0-3 suitable for use in a 4 entry IRQ domain. The way that works? Subtract one from the INTx value to obtain the hwirq number. Literally it, no cap ✨

Returns 0 on success, or -EINVAL if the interrupt specifier is out of range. Vibe check: out-of-range gets the -EINVAL treatment 😭

🌈 SEE ALSO 🌈

The whole extended friend group, all exact and accounted for 🫶:

• Kernel file ./include/linux/pci.h — enum pci_interrupt_pin(9)
• pci_channel_state_t(9)
• pci_is_bridge(9)
• pci_is_vga(9)
• pci_is_display(9)
• struct pci_driver(9)
• PCI_DEVICE(9)
• PCI_DEVICE_DRIVER_OVERRIDE(9)
• PCI_DRIVER_OVERRIDE_DEVICE_VFIO(9)
• PCI_DEVICE_SUB(9)
• PCI_DEVICE_CLASS(9)
• PCI_VDEVICE(9)
• PCI_VDEVICE_SUB(9)
• PCI_DEVICE_DATA(9)
• pcie_capability_clear_and_set_word(9)
• pci_bus_for_each_resource(9)
• module_pci_driver(9)
• builtin_pci_driver(9)
• pci_irq_type(9)
• pci_resource_is_io(9)
• pci_resource_is_mem(9)
• pci_pcie_cap(9)
• pci_is_pcie(9)
• pcie_caps_reg(9)
• pci_pcie_type(9)
• pcie_find_root_port(9)
• pci_vpd_alloc(9)
• pci_vpd_find_id_string(9)
• pci_vpd_find_ro_info_keyword(9)
• pci_vpd_check_csum(9)
• pci_ari_enabled(9)
• pci_is_thunderbolt_attached(9)

and that's the whole page, bestie 💖 source/version: ./include/linux; date: October 2026; manual: pci_irqd_intx_xlate(9). slay and goodbye 🫶✨