serial_lsr_in(9)

💅 serial_lsr_in(9) — like, the manual name is right there bestie

okay so this is a page from the Kernel API Manual, and honestly? it's a little one but it's a whole vibe. sit down, we're talking about serial_lsr_in 🫶

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✨ NAME ✨

serial_lsr_in — reads the LSR register and preserves those flags across reads, no cap 💅

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🎀 SYNOPSIS 🎀

u16 serial_lsr_in (struct uart_8250_port *up );

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🦋 ARGUMENTS 🦋

• up — your uart 8250 port, the main character of this whole function 💖

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🌈 DESCRIPTION 🌈

okay so picture this: you read the LSR register, and some of the flags? not preserved across reads. rude, honestly 😭 so serial_lsr_in reads that LSR register and handles saving those non-preserved flags across reads for you, like a true bestie 🫶

the flags that are not preserved across reads get stored into up->lsr_saved_flags — that's where they live now, periodt 💅

and what does it give you back? the LSR value, or'ed together with the preserved flags (if any). iconic ✨

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🌟 SEE ALSO 🌟

• Kernel file ./drivers/tty/serial/8250/8250.h — go read it, iykyk 📖💜

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and that's the whole page, bestie!! it's giving short-but-sweet fr fr 🍓 this one lives in ./drivers/tty/serial/8250 and it's dated October 2026 — slay, see you next read 💖✨🎀