uart_change_pm(9)

💅 uart_change_pm — the kernel API manual, bestie edition ✨

okay so real talk, you're looking at uart_change_pm(9) from the Kernel API Manual and honestly? It's a tiny one but it's important, so let's get into it 🎀

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🌸 NAME 🌸

uart_change_pm — sets the power state of the port. that's it, that's the whole vibe ✨

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🦋 SYNOPSIS 🦋

void uart_change_pm (struct uart_state *state , enum uart_pm_state
pm_state );

like, she takes a struct uart_state * and an enum uart_pm_state and returns void. no drama, no return value, just vibes 💅

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🍓 ARGUMENTS 🍓

• state — the port descriptor. your little port bestie 💖
• pm_state — the new state. the glow-up she's getting ✨

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🔥 DESCRIPTION 🔥

Locking: port->mutex has to be held 🔒

no cap, this is the whole description. before you call her, you must be holding port->mutex — that's the rule, periodt. don't be the person who skips the lock, i'm literally begging 🙈

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👑 SEE ALSO 👑

Kernel file ./drivers/tty/serial/serial_core.c — and her whole friend group, fr fr:

• uart_write_wakeup(9)
• uart_update_timeout(9)
• uart_get_baud_rate(9)
• uart_get_divisor(9)
• uart_get_lsr_info(9)
• uart_console_write(9)
• uart_parse_earlycon(9)
• uart_parse_options(9)
• uart_set_options(9)
• uart_register_driver(9)
• uart_unregister_driver(9)
• serial_core_add_one_port(9)
• serial_core_remove_one_port(9)
• uart_match_port(9)
• uart_handle_dcd_change(9)
• uart_handle_cts_change(9)
• uart_insert_char(9)
• uart_try_toggle_sysrq(9)
• uart_get_rs485_mode(9)

like, that's the whole group chat, iykyk 🫶

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and that's the page!! mwah 💋 this cutie lives over in ./drivers/tty/serial, and the version on deck is from October 2026 — go forth and set those power states responsibly, bestie 🌈⭐