gsm_fcs_add_block(9)

💅 gsm_fcs_add_block — the Kernel API Manual, section 9, bestie

Okay so real talk: this is gsm_fcs_add_block(9), straight out of the Kernel API Manual, section 9. She's a tiny little function but she's doing her job and honestly? We respect her.

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🌸 NAME 🌸

gsm_fcs_add_block — update the FCS for a block, periodt.

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✨ SYNOPSIS ✨

u8 gsm_fcs_add_block (u8 fcs , u8 *c , int len );

That's it. That's the whole vibe check. 🫶

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🎀 ARGUMENTS 🎀

• fcs — the Current FCS, like the one you already have in your hand. Your starting point, your pre-existing lore.
• c — a buffer of data. Just... a whole pile of bytes. A little snack pack of them.
• len — the length of that buffer. Because obviously we need to know how many bytes we're snacking on, ngl.

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🦋 DESCRIPTION 🦋

Update the FCS so it includes c, okay?

She uses the algorithm in the specification notes — not me making stuff up, that's literally what the manpage says, iykyk. No cap, no extra creative liberties, just the spec notes algorithm doing its thing. 💅

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🔥 SEE ALSO 🔥

Huge friend group energy here — this is the whole group chat, in order, and every single one of them is invited. It's giving linked list of besties. Kernel file ./drivers/tty/n_gsm.c is the shared apartment they all live in 🏠 and then we have:

gsm_fcs_add(9), gsm_read_ea(9), gsm_read_ea_val(9), gsm_encode_modem(9), gsm_encode_params(9), gsm_register_devices(9), gsm_unregister_devices(9), gsm_print_packet(9), gsm_stuff_frame(9), gsm_send(9), gsm_dlci_clear_queues(9), gsm_response(9), gsm_command(9), gsm_data_alloc(9), gsm_send_packet(9), gsm_is_flow_ctrl_msg(9), gsm_data_kick(9), __gsm_data_queue(9), gsm_data_queue(9), gsm_dlci_data_output(9), gsm_dlci_data_output_framed(9), gsm_dlci_modem_output(9), gsm_dlci_data_sweep(9), gsm_dlci_data_kick(9), gsm_control_command(9), gsm_control_reply(9), gsm_process_modem(9), gsm_process_negotiation(9), gsm_control_modem(9), gsm_control_negotiation(9), gsm_control_rls(9), gsm_control_message(9), gsm_control_response(9), gsm_control_keep_alive(9), gsm_control_transmit(9), gsm_control_retransmit(9), gsm_control_send(9), gsm_control_wait(9), gsm_dlci_close(9), gsm_dlci_open(9), gsm_dlci_negotiate(9), gsm_dlci_t1(9), gsm_dlci_begin_open(9), gsm_dlci_set_opening(9), gsm_dlci_set_wait_config(9), gsm_dlci_begin_close(9), gsm_dlci_data(9), gsm_dlci_command(9), gsm_kick_timer(9), gsm_dlci_copy_config_values(9), gsm_dlci_config(9), gsm_dlci_alloc(9), gsm_dlci_free(9), gsm_dlci_release(9), gsm_queue(9), gsm0_receive_state_check_and_fix(9), gsm0_receive(9), gsm1_receive_state_check_and_fix(9), gsm1_receive(9), gsm_error(9), gsm_cleanup_mux(9), gsm_activate_mux(9), gsm_free_mux(9), gsm_free_muxr(9), gsm_alloc_mux(9), gsmld_output(9), gsmld_write_trigger(9), gsmld_write_task(9), gsmld_attach_gsm(9), gsmld_detach_gsm(9), gsmld_flush_buffer(9), gsmld_close(9), gsmld_open(9), gsmld_write_wakeup(9), gsmld_read(9), gsmld_write(9), gsmld_poll(9), gsm_modem_upd_via_data(9), gsm_modem_upd_via_msc(9), gsm_modem_update(9), gsm_wait_modem_change(9)

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and that's the whole page, mwah 💖

Cute lil sign-off time: this page lives under ./drivers/tty, it's dated October 2026, and it's filed as gsm_fcs_add_block(9). Slay. Go update your FCS bestie 🌈⭐👑