usb_hcd_alloc_bandwidth(9)

💖 usb_hcd_alloc_bandwidth(9) — Kernel API Manual 💖

okay so bestie, we're in the Kernel API Manual and this page is the bandwidth vibe check. lowkey essential when USB configs are switching up. no cap. 💅

🌸 NAME 🌸

usb_hcd_alloc_bandwidth — check whether a new bandwidth setting exceeds the bus bandwidth. ✨

🦋 SYNOPSIS 🦋

int usb_hcd_alloc_bandwidth (struct usb_device *udev , struct
       usb_host_config *new_config , struct usb_host_interface *cur_alt ,
       struct usb_host_interface *new_alt );

🎀 ARGUMENTS 🎀

• udev — the target usb_device 👑
• new_config — the new configuration to install 🌈
• cur_alt — the current alternate interface setting 🦋
• new_alt — the alternate interface setting that is being installed ✨

💫 DESCRIPTION 💫

okay so here's the group chat on how to use it, bestie:

• Changing configurations: pass the new configuration in new_config, and pass NULL for cur_alt and new_alt. slay 🫶
• Resetting a device's configuration — this puts the device in the ADDRESSED state: pass NULL for new_config, cur_alt, and new_alt. periodt 💅
• Changing alternate interface settings: pass NULL for new_config, pass the current alternate interface setting in cur_alt, and pass the new alternate interface setting in new_alt. it's giving precise. 🌸

🔥 RETURN 🔥

An error if the requested bandwidth change exceeds the bus bandwidth or host controller internal resources. that's the whole vibe check, bestie 💀

⭐ SEE ALSO ⭐

Kernel file ./drivers/usb/core/hcd.c is in the mix, along with: ascii2desc(9), rh_string(9), usb_bus_init(9), usb_register_bus(9), usb_deregister_bus(9), register_root_hub(9), usb_calc_bus_time(9), usb_hcd_link_urb_to_ep(9), usb_hcd_check_unlink_urb(9), usb_hcd_unlink_urb_from_ep(9), usb_hcd_giveback_urb(9), usb_hcd_reset_endpoint(9), usb_alloc_streams(9), usb_free_streams(9), usb_hcd_resume_root_hub(9), usb_bus_start_enum(9), usb_hcd_irq(9), usb_hc_died(9), usb_create_shared_hcd(9), usb_create_hcd(9), usb_stop_hcd(9), usb_add_hcd(9), usb_remove_hcd(9). iykyk 🦋

mwah 💋 — source/version: ./drivers/usb/core; date: October 2026. byeee bestie, go check that bandwidth 🫶✨