dwc2_gadget_get_chain_limit(9)

💅 dwc2_gadget_get_chain_limit(9) — like, the kernel API manual bestie ✨

okay so real talk, this is a page straight out of the Kernel API Manual and it's lowkey iconic. the function is dwc2_gadget_get_chain_limit, and it's here to tell you how much data you can yeet at an endpoint in one go before the DMA descriptor chain runs out of room. no cap. 🎀

✨ NAME ✨

dwc2_gadget_get_chain_limit — get the maximum data payload value of the DMA descriptor chain prepared for specific endpoint 🦋

🌸 SYNOPSIS 🌸

unsigned int dwc2_gadget_get_chain_limit (struct dwc2_hsotg_ep *hs_ep );

🎀 ARGUMENTS 🎀

• hs_ep — The endpoint 💖 (that's it, that's the arg, she's simple and she knows what she wants)

🔥 DESCRIPTION 🔥

So what does she do? She returns the maximum data that can be queued in one go on a given endpoint, and that number depends on its descriptor chain capacity. the whole point is so that transfers that are too long can be split. it's giving "know your limits before you embarrass yourself" energy, and honestly? we respect it. 👑

💜 SEE ALSO 💜

the Kernel file ./drivers/usb/dwc2/gadget.c is the main character here, and she brought her whole friend group:

• using_dma(9)
• dwc2_gadget_incr_frame_num(9)
• dwc2_gadget_dec_frame_num_by_one(9)
• dwc2_hsotg_en_gsint(9)
• dwc2_hsotg_disable_gsint(9)
• dwc2_hsotg_ctrl_epint(9)
• dwc2_hsotg_tx_fifo_count(9)
• dwc2_hsotg_tx_fifo_total_depth(9)
• dwc2_gadget_wkup_alert_handler(9)
• dwc2_hsotg_tx_fifo_average_depth(9)
• dwc2_hsotg_init_fifo(9)
• dwc2_hsotg_ep_alloc_request(9)
• is_ep_periodic(9)
• dwc2_hsotg_unmap_dma(9)
• dwc2_hsotg_write_fifo(9)
• get_ep_limit(9)
• dwc2_hsotg_read_frameno(9)
• dwc2_hsotg_start_req(9)
• dwc2_hsotg_map_dma(9)
• dwc2_gadget_target_frame_elapsed(9)
• dwc2_hsotg_complete_oursetup(9)
• ep_from_windex(9)
• dwc2_hsotg_set_test_mode(9)
• dwc2_hsotg_send_reply(9)
• dwc2_hsotg_process_req_status(9)
• get_ep_head(9)
• dwc2_gadget_start_next_request(9)
• dwc2_hsotg_process_req_feature(9)
• dwc2_hsotg_stall_ep0(9)
• dwc2_hsotg_process_control(9)
• dwc2_hsotg_complete_setup(9)
• dwc2_hsotg_enqueue_setup(9)
• dwc2_hsotg_complete_request(9)
• dwc2_hsotg_rx_data(9)
• dwc2_hsotg_ep0_zlp(9)
• dwc2_hsotg_handle_outdone(9)
• dwc2_hsotg_handle_rx(9)
• dwc2_hsotg_ep0_mps(9)
• dwc2_hsotg_set_ep_maxpacket(9)
• dwc2_hsotg_txfifo_flush(9)
• dwc2_hsotg_trytx(9)
• dwc2_hsotg_complete_in(9)
• dwc2_gadget_read_ep_interrupts(9)
• dwc2_gadget_handle_ep_disabled(9)
• dwc2_gadget_handle_out_token_ep_disabled(9)
• dwc2_gadget_handle_nak(9)
• dwc2_hsotg_epint(9)
• dwc2_hsotg_irq_enumdone(9)
• kill_all_requests(9)
• dwc2_hsotg_disconnect(9)
• dwc2_hsotg_irq_fifoempty(9)
• dwc2_hsotg_core_init_disconnected(9)
• dwc2_gadget_handle_incomplete_isoc_in(9)
• dwc2_gadget_handle_incomplete_isoc_out(9)
• dwc2_hsotg_irq(9)
• dwc2_hsotg_ep_enable(9)
• dwc2_hsotg_ep_disable(9)
• on_list(9)
• dwc2_hsotg_ep_dequeue(9)
• dwc2_gadget_ep_set_wedge(9)
• dwc2_hsotg_ep_sethalt(9)
• dwc2_hsotg_ep_sethalt_lock(9)
• dwc2_hsotg_init(9)
• dwc2_hsotg_udc_start(9)
• dwc2_hsotg_udc_stop(9)
• dwc2_hsotg_gadget_getframe(9)
• dwc2_hsotg_set_selfpowered(9)
• dwc2_hsotg_pullup(9)
• dwc2_hsotg_vbus_draw(9)
• dwc2_hsotg_initep(9)
• dwc2_hsotg_hw_cfg(9)
• dwc2_hsotg_dump(9)
• dwc2_gadget_init(9)
• dwc2_hsotg_remove(9)
• dwc2_backup_device_registers(9)
• dwc2_restore_device_registers(9)
• dwc2_gadget_init_lpm(9)
• dwc2_gadget_program_ref_clk(9)
• dwc2_gadget_enter_hibernation(9)
• dwc2_gadget_exit_hibernation(9)
• dwc2_gadget_enter_partial_power_down(9)
• dwc2_gadget_enter_clock_gating(9)

like I said. the whole friend group. invite them all to the group chat, they're lovely 🫶

and that's the tea, bestie 💅 this lil slice of kernel lore lives in ./drivers/usb/dwc2, dated October 2026 — screenshot it, cite it, put it on your lock screen, whatever, it's yours now. mwah 😭💖