pci_enable_acs(9)

💅 pci_enable_acs — Kernel API Manual

okay so this is from the Kernel API Manual bestie, section 9, and it's a tiny little function with a big main character job: turning on ACS when the hardware actually supports it. no cap. it's giving "short but mighty" ✨

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🌸 NAME 🌸

pci_enable_acs — enable ACS if hardware support it

like, the whole personality. if the hardware doesn't support it, this function simply does not have the range. 🙈

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🎀 SYNOPSIS 🎀

void pci_enable_acs (struct pci_dev *dev );

literally returns nothing (void), takes one pointer, and minds its own business. periodt. 💅

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🦋 ARGUMENTS 🦋

• dev — the PCI device 💖 the one and only thing you hand it. the device we're trying to get ACS-enabled, iykyk.

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⭐ SEE ALSO ⭐

oookay buckle up because this list is long — it's giving "the whole PCI posse pulled up". 🫶 every single one is in the kernel file ./drivers/pci/pci.c, and here they all are, sorted by vibe:

• capability-hunting & bus stuff: pci_bus_max_busnr(9), pci_status_get_and_clear_errors(9), pci_dev_str_match_path(9), pci_dev_str_match(9), pci_find_capability(9), pci_bus_find_capability(9), pci_find_next_ext_capability(9), pci_find_ext_capability(9), pci_get_dsn(9), pci_find_next_ht_capability(9), pci_find_ht_capability(9), pci_find_vsec_capability(9), pci_find_dvsec_capability(9), pci_find_parent_resource(9), pci_find_resource(9), pci_resource_name(9), pci_wait_for_pending(9), pci_request_acs(9), pci_std_enable_acs(9)
• power management girlies (the biggest group, obviously): pci_restore_bars(9), pci_update_current_state(9), pci_refresh_power_state(9), pci_platform_power_transition(9), pci_resume_bus(9), pci_power_up(9), pci_set_full_power_state(9), __pci_dev_set_current_state(9), pci_bus_set_current_state(9), pci_set_low_power_state(9), pci_set_power_state(9), pci_save_state(9), pci_restore_state(9), pci_store_saved_state(9), pci_load_saved_state(9), pci_load_and_free_saved_state(9), pci_reenable_device(9), pci_enable_device_mem(9), pci_enable_device(9), pcibios_release_device(9), pcibios_disable_device(9), pci_disable_enabled_device(9), pci_disable_device(9), pcibios_set_pcie_reset_state(9), pci_set_pcie_reset_state(9), pcie_clear_root_pme_status(9), pci_check_pme_status(9), pci_pme_wakeup(9), pci_pme_wakeup_bus(9), pci_pme_capable(9), pci_pme_restore(9), pci_pme_active(9), __pci_enable_wake(9), pci_enable_wake(9), pci_wake_from_d3(9), pci_target_state(9), pci_prepare_to_sleep(9), pci_back_from_sleep(9), pci_finish_runtime_suspend(9), pci_dev_run_wake(9), pci_dev_need_resume(9), pci_dev_adjust_pme(9), pci_dev_complete_resume(9), pci_choose_state(9), pci_suspend_retains_context(9), pci_bridge_d3_possible(9), pci_d3cold_enable(9), pci_d3cold_disable(9), pci_pm_init(9), _pci_add_cap_save_buffer(9), pci_allocate_cap_save_buffers(9), pci_configure_ari(9), pci_acs_enabled(9), pci_acs_path_enabled(9), pci_acs_init(9), pci_enable_atomic_ops_to_root(9)
• regions, master bits & mwi: pci_release_region(9), __pci_request_region(9), pci_request_region(9), pci_release_selected_regions(9), pci_request_selected_regions(9), pci_request_selected_regions_exclusive(9), pci_release_regions(9), pci_request_regions(9), pci_request_regions_exclusive(9), pci_remap_iospace(9), pci_unmap_iospace(9), pcibios_setup(9), pcibios_set_master(9), pci_set_master(9), pci_clear_master(9), pci_set_cacheline_size(9), pci_set_mwi(9), pci_try_set_mwi(9), pci_clear_mwi(9), pci_disable_parity(9), pci_intx(9), pci_wait_for_pending_transaction(9)
• reset squad: pcie_flr(9), pcie_reset_flr(9), pci_pm_reset(9), pcie_wait_for_link_status(9), pcie_retrain_link(9), pcie_wait_for_link_delay(9), pcie_wait_for_link(9), pci_bridge_wait_for_secondary_bus(9), pci_bridge_secondary_bus_reset(9), __pci_reset_function_locked(9), pci_init_reset_methods(9), pci_reset_function(9), pci_reset_function_locked(9), pci_try_reset_function(9), pci_probe_reset_slot(9), pci_try_reset_slot(9), pci_try_reset_bus(9), pci_reset_bridge(9), pci_bus_error_reset(9), pci_probe_reset_bus(9), pci_reset_bus(9)
• link speed / width / bandwidth core: pcix_get_max_mmrbc(9), pcix_get_mmrbc(9), pcix_set_mmrbc(9), pcie_get_readrq(9), pcie_set_readrq(9), pcie_get_mps(9), pcie_set_mps(9), pcie_bandwidth_available(9), pcie_get_supported_speeds(9), pcie_get_speed_cap(9), pcie_get_width_cap(9), pcie_bandwidth_capable(9), __pcie_print_link_status(9), pcie_print_link_status(9)
• and the rest of the friend group: pci_select_bars(9), pci_set_vga_state(9), pci_add_dma_alias(9), pci_real_dma_dev(9), pci_specified_resource_alignment(9), pci_bus_find_emul_domain_nr(9), pci_ext_cfg_avail(9)

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lowkey a reminder bestie: this page lives in ./drivers/pci 💖 and it's dated October 2026 — so if you're reading it in a different era, that's the version you've got. slay. 🎀✨🦋