After my mother passed away I ended up with a big box full of old film negatives containing photos from childhood family trips and similar. So I decided to buy a negative photo scanner and found that the Plustek 8200i was supported under Linux so I bought that. Only to discover that the chipset in the scanner had changed to one that wasn’t supported under Linux anymore. So I had some success making Linux configuration tools for some of my hardware using Claude code, like my Dell Camera controller app so I thought, maybe Claude can help me get a working SANE driver. I basically got stuck and got nowhere for the longest time and even basically gave up on the project for a few Months.
Then I saw a post on X from Tom Crider aka Glorious Eggroll talking about how he had managed to fix a mouse driver using AI tooling. He basically described how he set it up so that the AI agent had full control of a Windows instance to capture data needed to fix the driver. So I pasted his tweet into Claude and asked it to help me set up a windows virtual machine to do the same things Tom as doing for my scanner. I think the combination of having the ability to run scans under windows and capture the USB data while doing so worked wonders, probably combined with improvements to Claude code made a huge difference. Within a few hours I had my first ever working scan under Linux, sure with some quality issues, but 100% recognizable as the image in the negative. Some days later I had a near perfect driver, including support for Infrared scanning ready to go, only to discover that in the time between me giving up and then trying again someone had committed code to SANE to support the scanner already…..it happens sometimes. I also used Claude to write an application for doing negative scanning, which I named Negative Vibes, thought that was a cute name.
Anyway, with the success of my scanner effort I thought, I wonder if I can use this to finally fix the last issues with MIPI camera support on my laptop. So I told claude to re-use the harness I had created and try to fix the MIPI camera on my laptop by updating the kernel driver and libcamera as needed. I started the job in the morning and by the end of the day I had a much improved situation with patches for both the kernel and libcamera ready.
So I thought that this might be worthwhile sharing with the world, and while anyone could start from scratch I did ask Claude to make the harness generic and document it to make the pathway for anyone else who wants to try this on their hardware a little easier. Writing a driver for undocumented hardware has always been tedious. You capture bus traffic, stare at hex dumps, and form hypotheses about what each register or control transfer does. You then test them one at a time, usually for weeks. None of it is conceptually hard, but it takes a lot of patience and skills.
That kind of work suits an AI model well. It can read thousands of lines of USB capture, notice that a sequence repeats with one byte changing, and propose what that byte means. It can write the test to confirm it, and it doesn’t get bored. The human still decides what to build and checks that it works on real hardware, but the slog shrinks a lot.
Be aware that I did not use hw-harness in this form for my projects as this was basically bespoke code at that time, so this project is an attempt to make the harness more generic and shareable from the scripts I was using while doing the work. What hw-harness is meant to help your Claude or Codex session with:
1. Record a reference session. Run the vendor’s Windows driver in a KVM virtual machine, with the real device passed through to the guest.
For devices with no bus to tap, such as an internal MIPI camera, the harness uses Windows-side inspection instead. That means INF files, registry data, ACPI tables and device properties.
The approach should be fine in the sense it doesn’t rely on copying any code instead it observes what the hardware does and only extract configuration data from the Windows drivers, so every constant in the new driver traces back to something recorded.
So for those interested I have 3 short descriptions of the projects I did and what was needed.
Project 1: a SANE backend for the Plustek OpticFilm 8200i
Comparing the driver output of two drivers available.