es58x_check_rx_urb(9)

💅 es58x_check_rx_urb(9) — like, the vibe check for your incoming URB commands

okay so this is a page straight out of the Kernel API Manual (yes, the kernel has a manual, and yes it's lowkey iconic) and today's main character is es58x_check_rx_urb. bestie, it's literally the bouncer at the club door of your ES58X device — it looks at each incoming URB command and goes "hmm, are you valid or are you a mess?" 🎀

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✨ NAME ✨

es58x_check_rx_urb — checks the length and the format of the URB command, no cap.

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🌸 SYNOPSIS 🌸

signed int es58x_check_rx_urb (struct es58x_device *es58x_dev ,
                               const union es58x_urb_cmd *urb_cmd ,
                               u32 urb_actual_len );

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🦋 ARGUMENTS 🦋

• es58x_dev — your ES58X device, the one and only. 💖
• urb_cmd — the URB command that came back from the ES58X device. heads up: it might not be aligned, so don't go assuming it's all neat and pretty. 🫶
• urb_actual_len — the actual length of that URB command. like, the real one, fr fr.

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👑 DESCRIPTION 👑

so what it does is check whether the first message of the received urb is valid — which basically means the header and the length are coherent with each other. both of them. together. it's giving teamwork. ✨

and it returns these little gremlins when things go sideways:

• -ENODATA if the URB command is incomplete — in which case the URB command should be buffered and combined with the next URB to try to reconstitute the URB command. yes, it's a puzzle piece situation, we're rebuilding it. 🧩
• -EOVERFLOW if the length is bigger than the maximum expected one. too much. absolutely too much. 💀
• -EBADRQC if the start of frame does not match the expected value. wrong vibe at the door, respectfully denied. 🙈

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⭐ RETURN ⭐

on success it returns the length of the first message of the URB. slay. 👑

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🌈 SEE ALSO 🌈

the kernel file itself, live and in person:

Kernel file ./drivers/net/can/usb/etas_es58x/es58x_core.c

and the whole friend group, all of them, in order, no one gets left out 🫶:

• es58x_calculate_crc(9), es58x_get_crc(9), es58x_set_crc(9), es58x_check_crc(9), es58x_timestamp_to_ns(9), es58x_set_skb_timestamp(9), es58x_rx_timestamp(9), es58x_set_realtime_diff_ns(9), es58x_is_can_state_active(9), es58x_is_echo_skb_threshold_reached(9), es58x_can_free_echo_skb_tail(9), es58x_can_get_echo_skb_recovery(9), es58x_can_get_echo_skb(9), es58x_can_reset_echo_fifo(9), es58x_flush_pending_tx_msg(9), es58x_tx_ack_msg(9), es58x_rx_can_msg(9), es58x_rx_err_msg(9), es58x_cmd_ret_desc(9), es58x_rx_cmd_ret_u8(9), es58x_rx_cmd_ret_u32(9), es58x_increment_rx_errors(9), es58x_handle_urb_cmd(9), es58x_copy_to_cmd_buf(9), es58x_split_urb_try_recovery(9), es58x_handle_incomplete_cmd(9), es58x_split_urb(9), es58x_read_bulk_callback(9), es58x_write_bulk_callback(9), es58x_alloc_urb(9), es58x_get_tx_urb(9), es58x_submit_urb(9), es58x_send_msg(9), es58x_alloc_rx_urbs(9), es58x_free_urbs(9), es58x_open(9), es58x_stop(9), es58x_xmit_commit(9), es58x_xmit_more(9), es58x_start_xmit(9), es58x_set_mode(9), es58x_init_priv(9), es58x_init_netdev(9), es58x_free_netdevs(9), es58x_init_es58x_dev(9), es58x_probe(9), es58x_disconnect(9)

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ok that's the whole page, you ate that 💅 go forth and validate those URBs bestie, and remember: incomplete is not invalid, it just needs a friend 🥺

later babes 💜 this one lives in ./drivers/net/can/usb/etas_es58x, dated October 2026, and it's filed under es58x_check_rx_urb(9) in case you ever need to find it again 🎀✨