pci_msix_vec_count(9)

💅 pci_msix_vec_count(9) 💅

okay so this is a page from the Kernel API Manual and it's genuinely one of the shorter ones bestie, so we can absolutely get through it together 🫶

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✨ NAME ✨

pci_msix_vec_count — Get number of MSI-X interrupt vectors on device

like, it just counts your vectors. that's the whole job. icon behaviour honestly 👑

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🌸 SYNOPSIS 🌸

int pci_msix_vec_count (struct pci_dev *dev );

that's it. one function, one argument, one int coming back at you 💖

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🎀 ARGUMENTS 🎀

• dev — the PCI device to operate on. literally just hand it the device you're curious about and it'll do its thing ✨

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🦋 RETURN 🦋

so here's what you get back, and there are three (3) whole vibes:

• the number of MSI-X interrupt vectors available on this device — that's the device's MSI-X capability structure "table size", no cap 💅
• -EINVAL — if the device is not MSI-X capable 😭 like sorry bestie, wrong device
• other errnos otherwise — the general "something else went sideways" bucket 🙈

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👑 SEE ALSO 👑

kernel file ./drivers/pci/msi/api.c — that's where this lives, go read it if you're feeling studious 🧚

and the whole friend group of related calls, all of them, in order:

• pci_enable_msi(9)
• pci_disable_msi(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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ngl this one's short but it ate. go count some vectors 🍓

and that's the whole page!! brought to you by ./drivers/pci/msi, dated October 2026, filed under pci_msix_vec_count(9) — mwah, stan 💜🌈