pci_enable_msi(9)

💅 pci_enable_msi(9) 💅

okay so we're deep in the Kernel API Manual today bestie, and this one is literally the classic "enable MSI interrupts on your PCI device" situation ✨

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🌸 NAME 🌸

pci_enable_msi — Enable MSI interrupt mode on device

Like, that's it. That's the whole job. It turns on MSI interrupt mode for a device. Slay 🎀

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✨ SYNOPSIS ✨

int pci_enable_msi (struct pci_dev *dev );

one function, one argument, one int coming back at you 💖

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🫶 ARGUMENTS 🫶

• dev — the PCI device to operate on. just... the device. the one you want to mess with. no cap 🦋

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🔥 DESCRIPTION 🔥

okay so here's the tea ☕ — this is the legacy device driver API for enabling MSI interrupts mode on a device and allocating a single interrupt vector. both things, one call. iconic behavior honestly.

on success, the allocated vector's Linux IRQ gets saved at dev->irq, so that's where you go look for it 👀

and listen — the driver must invoke pci_disable_msi on cleanup. that's not optional, that's a whole commitment. you enabled it, you clean it up. periodt 💅

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⚠️ NOTE ⚠️

bestie. hear me. the newer pci_alloc_irq_vectors / pci_free_irq_vectors API pair should, in general, be used instead. like — in general. we're just being honest with you here 🙈

this is the legacy path! the docs themselves are telling you the newer pair is the move. no drama, just facts 💜

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🌈 RETURN 🌈

• 0 on success 🎉
• errno otherwise 😭

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💀 SEE ALSO 💀

Kernel file ./drivers/pci/msi/api.c — and all the sibling functions, because family is everything 🫶

• pci_disable_msi(9)
• pci_msix_vec_count(9)
• pci_enable_msix_range(9)
• pci_msix_can_alloc_dyn(9)
• pci_msix_alloc_irq_at(9)
• pci_msix_free_irq(9)
• pci_disable_msix(9)
• pci_alloc_irq_vectors(9)
• pci_alloc_irq_vectors_affinity(9)
• pci_irq_vector(9)
• pci_irq_get_affinity(9)
• pci_free_irq_vectors(9)
• pci_restore_msi_state(9)
• pci_msi_enabled(9)

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okay that's the whole page bestie, go enable those interrupts responsibly 💖

signing off from ./drivers/pci/msi — October 2026 edition, pci_enable_msi(9), mwah 👑✨