pci_scan_child_bus_extend(9)

💅 pci_scan_child_bus_extend — like, the Linux Kernel API Manual page for it, bestie 🎀

okay so real talk, this is pci_scan_child_bus_extend(9) from the Kernel API Manual, and it's genuinely one of those functions that sounds scary but is actually just "go look at everything under this bus, and also plan ahead for hotplug." we love a forward-thinking icon ✨

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✨ NAME ✨

pci_scan_child_bus_extend — scan devices below a bus 🦋

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🌸 SYNOPSIS 🌸

unsigned int pci_scan_child_bus_extend (struct pci_bus *bus , unsigned
       int available_buses );

like, that's the whole signature, no cap 💅

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💖 ARGUMENTS 💖

• bus — the bus you're scanning for devices. that's the main character right there 👑
• available_buses — the total number of buses you've got available. and btw, 0 means it does not try to extend beyond the minimal. so if you pass 0, it stays in its lane, respectfully 🙈

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🔥 DESCRIPTION 🔥

so what it does: it scans devices below bus, including the subordinate buses. then it returns the new subordinate number, which includes all the devices it found. literally just hands you back the updated count, periodt ✨

and here's the slay part — passing available_buses causes the remaining bus space to be distributed equally between hotplug-capable bridges, so the hierarchy can be extended later. it's giving "planning for your future self" energy and honestly? obsessed 🫶

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🌈 SEE ALSO 🌈

kernel file ./drivers/pci/probe.c — and the whole squad of related pages:

• __pci_size_bars(9)
• __pci_read_base(9)
• pcie_get_link_speed(9)
• pci_ea_fixed_busnrs(9)
• pci_ext_cfg_is_aliased(9)
• pci_cfg_space_size_ext(9)
• pci_intx_mask_broken(9)
• pci_setup_device(9)
• pcie_relaxed_ordering_enabled(9)
• pci_release_dev(9)
• pci_scan_slot(9)
• pci_scan_child_bus(9)
• pcibios_root_bridge_prepare(9)
• pci_rescan_bus_bridge_resize(9)
• pci_rescan_bus(9)

every single one of them, no skips, iykyk 💀💜

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okay bye bestie, that's the whole page — brought to you by ./drivers/pci, dated October 2026, from the Kernel API Manual set. go scan some buses, you've got this 🧚‍♀️💖⭐