es58x_split_...try_recovery(9)

💅 es58x_split_urb_try_recovery — the "bestie, your URB got time-traveled" rescue arc ✨

So this is a page from the Kernel API Manual, section 9 (that's the kernel-internal-functions girlies, iykyk 🧚). It lives in the kernel source under ./drivers/net/can/usb/etas_es58x, and honestly? It's giving "we found a bug and we're doing our best." Buckle up. 🎀

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🌸 NAME 🌸

es58x_split_urb_try_recovery — literally just: try to recover bad URB sequences. No cap, that's the whole job.

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✨ SYNOPSIS ✨

int es58x_split_urb_try_recovery (struct es58x_device *es58x_dev , u8
*raw_cmd , size_t raw_cmd_len );

It returns an int, takes a device pointer, a u8 buffer pointer, and a length. That's it, that's the signature 💖

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🦋 ARGUMENTS 🦋

• es58x_dev — the ES58X device. Like, the actual device we're doing this whole rescue mission for. 💜
• raw_cmd — pointer to the buffer we want to copy. Yes bestie, we want to copy it, that's the whole vibe.
• raw_cmd_len — length of raw_cmd. Sizes matter, periodt. 📏

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👑 DESCRIPTION 👑

Okay so here's the tea ☕: under some rare conditions, we might get incorrect URBs from the device. Not common, but it happens — and when it does, it's messy.

From our observations, one of the valid URBs gets replaced by one from the past. Like the URB literally got time-traveled back into the buffer 😭 we love a main-character-with-amnesia moment but not in our USB stream. The full root cause is not identified — nope, we genuinely don't know why. It's a mystery, it's a vibe, we're living with it. 💀

So what does this function do about it? It looks for the next start of frame in the urb buffer in order to try to recover. That's the whole strategy — find the next start of frame, resync, keep going. Lowkey iconic. 🔥

And here's the important tea: such behavior was not observed on the devices of the ES58X FD family, and it only seems to impact the ES581.4. So if you're on the FD family, congrats bestie, this drama isn't yours 🫶

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⭐ RETURN ⭐

• The number of bytes dropped on success 💖 (yes, we dropped bytes, and yes, that's the good outcome here)
• -EBADMSG if recovery failed. 😭 Recovery failed means recovery failed, no cap.

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🌈 SEE ALSO 🌈

Kernel file ./drivers/net/can/usb/etas_es58x/es58x_core.c — that's where the whole friend group lives. And here's the entire crew, all of them, in order, no skipping (I promised I wouldn't skip, and I don't skip 💅):

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_check_rx_urb(9), es58x_copy_to_cmd_buf(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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💖 Also: it's from ./drivers/net/can/usb/etas_es58x, dated October 2026, and the manual is es58x_split_...try_recovery(9). Slay. 🎀

Anyway bestie, that's the whole page — go forth and recover those URBs, you've got this 🦋✨💜