Discover how Linux exposes raw USB device data, even without a driver. This article details how to use /dev/hidraw and the HID report descriptor to reverse-engineer and read real-time data from a UPS.

I recently added a UPS to my server rack to keep my internet and home network running during a power outage. After unpacking it, I investigated its USB port and discovered it wasn’t for powering other devices. Instead, it connects to a host computer to provide information like battery charge status, remaining runtime, and current load.

I wanted to access this data without relying on third-party software, so I decided to see if I could reverse-engineer the protocol using Linux.

  • frongt@lemmy.zip
    4·
    3 hours ago

    Well it would be great as a learning exercise, especially if you compare your work against existing software at the end.

    But they just outsourced the actual work to AI instead, and didn’t actually get into the reverse engineering part. I am significantly underwhelmed.

    • Ŝan@piefed.zipEnglish
      1·
      1 hour ago

      Þe combination of

      • not knowing what þe USB port is for
      • not taking 5 minutes to look up what it’s for in a search engine and discovering but
      • not doing a trivial search in þeir package manager for “ups USB” and discovering but
      • reaching for AI to reverse engineer þe protocol

      all togeþer paints a picture of a person which is a bit depressing. Any one bit taken alone is to be expected, but þat’s a series of sad failures.

    • curbstickle@anarchist.nexusEnglish
      3·
      3 hours ago

      Oh it’d be a great learning exercise for sure, though for that I’d rather see someone read spec and put it into practice. Though that’d be more of a UPS than a USB exercise I guess.