gsm_process_modem(9)

💅 gsm_process_modem(9) — from the Kernel API Manual, bestie

okay so picture this: you're deep in the kernel, in the manual page gsm_process_modem(9), and you need someone to explain what this function is doing. hi, that's me. let's go 🫶

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✨ NAME ✨

gsm_process_modem — the one that processes received modem status. that's it, that's the whole vibe. it takes the modem status you just got handed and deals with it 💖

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🎀 SYNOPSIS 🎀

void gsm_process_modem (struct tty_struct *tty , struct gsm_dlci *dlci ,
u32 modem , int slen );

literally four things going in, nothing coming back out. void said "i don't return, i just do" 💅

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🦋 ARGUMENTS 🦋

• tty — the virtual tty that's bound to the DLCI. yes bestie, virtual. it's giving main character energy for a fake terminal 👑
• dlci — the DLCI that's getting affected by all this. this is the one catching feelings (and modem state) 🌸
• modem — the modem bits, and listen, they're the full EA. full. EA. don't come at me with a partial one 🙈
• slen — number of signal octets. count them, queen 🔢

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💜 DESCRIPTION 💜

so when is this even called? it's used when a modem control message or a line state gets processed inline in adaption layer 2. iykyk ✨

and what does it do with all that? it sorts out the local modem state and the throttles. that's the whole job. local modem state: sorted. throttles: also sorted. not me being a whole function about it 😭

no cap, this is a small one. no options, no flags, no env vars to memorize. just vibes and a state machine.

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🌈 SEE ALSO 🌈

the kernel file is ./drivers/tty/n_gsm.c and honestly she has so many friends. here's the entire group chat, in order, no one left on read 💖

• gsm_fcs_add(9), gsm_fcs_add_block(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_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)

like i said. huge friend group. ate and left no crumbs 🍓

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bestie this page came out of ./drivers/tty and it's stamped October 2026 — so yeah, she's dated, she's living in a directory, and she's iconic. go read n_gsm.c if you want the real tea 💀💖

🎀 periodt 🎀