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[HN Gopher] Writing a basic Linux device driver when you know no...
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Writing a basic Linux device driver when you know nothing about
Linux drivers
Author : sbt567
Score : 248 points
Date : 2025-06-22 10:29 UTC (3 days ago)
web link (crescentro.se)
w3m dump (crescentro.se)
| ianlevesque wrote:
| It's a userspace USB HID driver in rust, which is honestly more
| interesting/applicable to me than a kernel driver, which is what
| I thought it meant from the title.
| ahartmetz wrote:
| > I also thought I'd message the vendor and ask them if they
| could share any specifications or docs regarding their protocol.
| To my surprise, Nanoleaf tech support responded to me within 4
| hours, with a full description of the protocol that's used both
| by the Desk Dock as well as their RGB strips.
|
| How cool is that? Too many vendors still think that they have
| valuable intellectual property in such relative trivialities. And
| that handing out the specs freely helps their competitors more
| than themselves.
| starkrights wrote:
| I had the same reaction. Nano leaf is extremely cool for that.
| baby_souffle wrote:
| This has to put them in the top 0.01% of companies that make
| consumer electronics.
|
| I can think of only a few companies that bother to publish
| any details... And most of them are focused on industrial
| customers where it isn't unreasonable to need certain
| protocol details for integration or even just compliance with
| certain regulatory systems.
|
| Maybe things are changing?
|
| I have noticed that some of the LED light controllers you see
| on AliExpress are leaning in to open firmware standards. 5
| years ago, you bought the controller and had to flash your
| own firmware. Now, there's an option at checkout to select an
| open source firmware. Some even have a USB port built in for
| flashing!
| Teknoman117 wrote:
| I almost had that experience with one of the popular PC liquid
| cooling hardware vendors around 10 years ago.
|
| I emailed them saying I'd be interested in developing drivers
| for their hardware for Linux as I was a happy customer and was
| immediately put in touch with one of the managers and their
| engineering team.
|
| Made quite a bit of progress before the whole thing was shut
| down because one of their component vendors threatened them
| saying it'd be a breach of their contract with them.
|
| Apparently that vendor sold a "datacenter" (non consumer)
| version of that hardware for which they charged a hefty license
| fee for the management software (which was Linux compatible).
|
| Jokes on them, someone reverse engineered the whole thing with
| a USB analyzer years later and published it XD. (not me)
| agentkilo wrote:
| Yeah that part of the article put a big smile on my face.
|
| I did the same thing back in college, when I was in a lab. We
| wanted to do some research on Wi-Fi signals, and I happened to
| own a bunch of Wi-Fi adaptors produced by SomeSmallTech Co.
| Ltd., which featured relatively new Atheros chips and didn't
| have Linux drivers at the time.
|
| So I sent an email to the company's public email address,
| asking for some datasheets, "for science". To my
| disappointment, presumably a PR person replied that they "don't
| have a company policy to collaborate with academic research".
| (But they did send a quick reply, kudos to that.)
|
| Funnily enough, years later I ended up working for said
| company. Naturally, when I first logged into the company
| network, I searched for the datasheets I asked for. There were
| "classified" watermarks all over the PDFs :)
| wiz21c wrote:
| > don't have a company policy to collaborate with academic
| research"
|
| Strangely they all have a tacit policy to build their
| products at least partly on the results of academic research.
| 2Gkashmiri wrote:
| I have a solar inveter from a company, aparticular German
| brand. I wanted to use home assistant with it so I needed rs232
| data.. tried the support and they asked me to sign an NDA.
|
| Okay, cool. I did with a fake name, address and everything and
| they sent a file..
|
| Turns out the file is available online.
|
| Facepalm pro Max.
|
| So my question is, what kind of "IP" is in a data sheet that
| needs protection ? And this isnt even some secret product but a
| generic solar product sold by millions.
|
| Rs-232 protocol ? Really ?
| wiz21c wrote:
| They have asked to the legal team who basically don't know
| shit about what us do and who will always take the most
| conservative approach possible. So you'll get either: no
| answer, a "NO" answer or an "NDA" answer.
| Mad_ad wrote:
| Was it Alpha-ESS? they make it so stupidly hard to get your
| information outside of their smartphone app.
| sysmax wrote:
| It's not the IP, it's sadly how people react. Some folks will
| be appreciative of help, credit to them. Others will
| immediately get back how they tried it, it didn't work and now
| they need you to rewrite everything, or do their project for
| them, or redesign your product to match what they want it to
| be. And if you politely refuse, it quickly escalates to threats
| of trashing your business through every channel, and other
| things.
|
| So, the safest thing to do is not give details at all, or
| "leak" them like another reply in this thread mentions.
| jonnypotty wrote:
| Thanks for this. Good read and also kinda inspiring.
| dabedee wrote:
| I really enjoyed the way this post was written, i.e. it includes
| the code, how it was run, the false paths, etc. You almost get to
| live through the author's journey and how he figured out just
| enough to get something working.
| kblissett wrote:
| I enjoyed this post, but I'm eager to hear what the next step
| would be for a real "production" userspace driver. Are these
| typically just daemons that are configured to run at start up?
| And then some configuration GUI communicates with it over a
| socket or something?
| shreddit wrote:
| > Let's run it again to make sure it was not a fluke!
|
| I understood that reference
| 0xbadcafebee wrote:
| I want to run FreeBSD on my laptop, but they don't have a
| [complete] driver for my wifi card. I've thought about diving
| into AI coding-assistant agents just to see if I could use one to
| finish throwing together a working driver... but figuring out the
| AI agents is frictiony enough that I'm leaving it be. (I'm not a
| VSCode user)
| buildbot wrote:
| Claude code, being a CLI interface, might be more your style?
| Expensive though
| fithisux wrote:
| AI can also be used to help reverse engineer blobs.
| LorenDB wrote:
| The author should probably have implemented support in OpenRGB
| instead to better benefit others, but this is cool nonetheless.
| fracus wrote:
| I wish this was done in C so I didn't have to learn Rust. But
| maybe it is time to learn Rust.
| dralley wrote:
| Rust isn't that difficult really. Easier in many ways than C if
| you're building normal software and not, like, a library of
| fancy data structures.
| jeroenhd wrote:
| This is using rusb, a Rust wrapper around libusb. libusb is
| still written in plain old C: https://libusb.info/
|
| If you don't want to learn a different programming language,
| you can take the exact same approach in any language you prefer
| and play along. You may need to turn the more object oriented
| calls into libusb_* calls, but if you're used to programming in
| C you probably won't have a problem getting that to work.
| VTimofeenko wrote:
| Excellent post! I have a Nanoleaf 3d thing that I was hoping to
| use as an ambilight-like thing for the TV, but the experience
| was... meh. I know about the Hyperion project and hope to set it
| up one day, but meanwhile I think I could try to repurpose this
| code to control the strip from a Linux box.
| rkagerer wrote:
| This is awesome!
|
| But it also makes me a little bit sad. The original parallel port
| and even ISA interface seemed so simple by comparison, with less
| layers of abstraction. Just run a wire, and write to a port.
|
| I remember when I was a kid, I found a breakout board in an
| electronics store's random clearance parts bin, with an ISA
| header on an edge. On a whim I took it home and wire-wrapped a
| 7-segment LED onto it. Power and ground were easy. Each segment
| was hooked to a data line, through a simple buffer IC. I cheated
| and used only a minimal number of address lines to feed the
| enable port (guessing through a simple AND gate or something). I
| was amazed when I wrote to that address and it worked the first
| time!
|
| I look at a protocol like USB, with hundreds of pages, and
| instead of that curious excitement and enablement I felt back
| then, I feel a bit overwhelmed.
| colechristensen wrote:
| I sometimes think about this, starting from scratch with a
| computer hardware and software stack that disallowed all of the
| layers of abstraction that have built up over the decades.
|
| Yeah many of the abstractions help with performance but maybe
| there's value giving up much of that performance in exchange
| for simplicity.
| rkagerer wrote:
| It would be neat to design a whole new contemporary stack
| from scratch.
| dmonitor wrote:
| This is exactly the kind of simple tutorial I was looking for a
| few years ago. I forget what the project was that I wanted this
| for, though, haha. Thank you for the writeup!
| bhasi wrote:
| The title was misleading because the author wrote a userspace
| Rust driver and not a Linux kernel driver in C.
| amelius wrote:
| Upon reading the title I thought this was going to be about how
| easy it is to write or modify a Linux driver when using a LLM
| even if you know nothing about the subject.
| fithisux wrote:
| There are many innovative OSes that are killed by the lack of
| Device Drivers.
|
| As a community we must find a way for tackling this issue.
|
| Micro-Kernels are a solution where one can run different OSes but
| they will reuse the same device driver servers.
|
| But it requires co-ordination and determination.
|
| Rust can be a solution for sure.
| jeroenhd wrote:
| Any programming language can be a solution, the programming
| language itself isn't the problem. Convincing device driver
| programmers around the world to come up with a universal API
| that includes all the possible features and works on every OS
| is.
|
| In this case, the cross-platform libusb should make this code
| work on either Linux or Windows (if you install the signed
| Windows drivers). If other operating systems port libusb, they
| get this code for free.
|
| Most "real" drivers still run in kernel mode, though, and not
| even Linux can keep their ABI stable (Windows has to, between
| releases, with the aid of compatibility wrappers that only work
| for a certain amount of releases).
|
| It would probably be worth it more forbBespoke operating
| systems to implement either the Windows API (like ReactOS does)
| or the Linux API (pick an LTS version) to get existing drivers
| to work. Unless you pay them, most driver programmers aren't
| going to bother with anything than Windows, maybe Linux,
| _possibly_ macOS.
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