UPD(4)

💅 UPD(4) — the USB Power Devices sensor, bestie edition 💅

okay so real quick: this is from the Kernel Interfaces Manual, section 4, and the page is literally called UPD(4). it's giving "niche but iconic" and honestly? we're obsessed. let's get into it 🫶

✨ NAME ✨

upd — the USB Power Devices sensor. that's it, that's the vibe 🦋

🎀 SYNOPSIS 🎀

upd* at uhidev?

periodt. that's the whole lineup 😌

💖 DESCRIPTION 💖

so the upd driver is literally the main character of monitoring. it provides support for monitoring various sensors provided by USB Power Devices (such as a UPS). like, it's the one holding the group chat together and keeping an eye on everything 🔥

all the supported sensor values are made available via the sysctl(8) interface — no cap, that's just how it is.

here's the full sensor lineup, and yes i'm listing every single one because they ALL matter 💅:

• BatteryPresent
• ShutdownImminent
• ACPresent
• PercentLoad
• Overload
• RelativeStateOfCharge
• AbsoluteStateOfCharge
• RemainingCapacity
• FullChargeCapacity
• Charging
• Discharging
• AtRateTimeToFull
• AtRateTimeToEmpty
• RunTimeToEmpty
• NeedReplacement

look at that roster. fifteen sensors. absolute icons, every one of them ✨👑

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🌈 SEE ALSO 🌈

• intro(4)
• uhidev(4)
• sensorsd.conf(5)
• sensorsd(8)
• sysctl(8)

and if you wanna read the source material (very scholarly of you, love that):

The USB Power Devices specification can be found at: https://www.usb.org/hid

🦋 HISTORY 🦋

the upd driver first appeared in OpenBSD 5.6. a true trailblazer, honestly — been serving looks since day one 💜

🌸 AUTHORS 🌸

the upd driver was written by Andre de Oliveira. we stan a legend 🫶👑

💀 BUGS 💀

okay so this is the part where we keep it real, because i love you and i'm not gonna lie to you 😭

the upd driver does not indicate device health via aggregate or individual sensor status. nope. not a thing. it simply does not do that.

so if you're a user who wishes to monitor upd status using sensorsd(8), you must manually establish “high” and “low” limits for sensor values of interest via sensorsd.conf(5). manually, bestie. by hand. you set those limits yourself. it's giving DIY but make it sensor config 🙈

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and that's the whole page! mwah 💋 this gem is from Debian, dated December 1, 2024 — the UPD(4) manual page, signed, sealed, slayed. go monitor something, i believe in you ⭐💖