BACKLIGHT(9)

💡 BACKLIGHT(9) — the kernel dev manual page, bestie edition

okay so this is the BACKLIGHT(9) page from the Kernel Developer's Manual, and it's all about backlight, backlight_register, backlight_destroy, BACKLIGHT_GET_STATUS, and BACKLIGHT_SET_STATUS — aka the BACKLIGHT methods. yes the name is in all caps twice, she's dramatic like that 💅

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✨ SYNOPSIS ✨

device backlight
#include <backlight_if.h>
#include <sys/sys/backlight.h>

int
BACKLIGHT_GET_STATUS(device_t bus, struct backlight_props *props);

int
BACKLIGHT_SET_STATUS(device_t bus, struct backlight_props *props);

struct cdev *
backlight_register(const char *name, device_t dev);

int
backlight_destroy(struct cdev *cdev);

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🌸 DESCRIPTION 🌸

so the backlight driver is literally the glow-up department for your panel — it gives you a generic way to handle a panel backlight. no cap, that's the whole vibe.

drivers for the backlight system register themselves globally using the backlight_register() function. and they're not allowed to be lazy about it — they must define two methods:

• BACKLIGHT_GET_STATUS() — the one you use to query the current brightness level 🔍
• BACKLIGHT_SET_STATUS() — the one you use to update it 🔥

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🎀 INTERFACE 🎀

• BACKLIGHT_GET_STATUS(device_t bus, struct backlight_props *props) — the driver fills in the current brightless level plus the optional supported levels. (yes, "brightless", that's genuinely what the page says, I'm not fixing it, it's iconic 💀)
• BACKLIGHT_SET_STATUS(device_t bus, struct backlight_props *props) — the driver updates the backlight level based on the brightness member of the props struct. straightforward, she ate. 👑

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🦋 FILES 🦋

• /dev/backlight/*

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🌈 SEE ALSO 🌈

• backlight(8)

(iykyk — go read that one next, bestie 🫶)

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⭐ HISTORY ⭐

the backlight interface first appear in FreeBSD 13.0. and the backlight driver + this manual page was written by Emmanuel Vadot <manu@FreeBSD.org>. absolute main character energy, we stan 💜

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fr fr, keep the two methods defined or the whole registration thing doesn't happen. that's not a suggestion, that's the whole assignment.

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okay that's the page!! sign-off time: this beauty came from Debian, dated October 2, 2020 🎀 go touch some brightness sliders bestie, mwah 💋✨