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Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

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Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#21

Post by ChickeNES »

bigstrat2003 wrote: post #17
SillyUsername wrote: post #2

I wrote* a modern Linux driver that supports ultrawide resolutions, higher refresh, and faster performance than the original driver(s) on this cheap HDMI only variant server GPU. I created it because I wanted my Nvidia GPUs to be compute only, and needed a cheap and small display GPU to run X11. I bought this GPU on AliExpress, after learning it had Linux support. It does, but kernel 5.x series and the sm750 driver i…

[flagged]

Don't you people have something better to do than hound people for their choice of tools?

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#22

Post by Brian_K_White »

bigstrat2003 wrote: post #17
SillyUsername wrote: post #2

I wrote* a modern Linux driver that supports ultrawide resolutions, higher refresh, and faster performance than the original driver(s) on this cheap HDMI only variant server GPU. I created it because I wanted my Nvidia GPUs to be compute only, and needed a cheap and small display GPU to run X11. I bought this GPU on AliExpress, after learning it had Linux support. It does, but kernel 5.x series and the sm750 driver i…

[flagged]

That's a thing that happens, but this doesn't look like that.

The words "I vibe coded this" explicitly disclaim any excess credit.

They did exactly what anyone can reasonably ask for. They exhibited essentially perfect integrity.

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#23

Post by SillyUsername »

cromka wrote: post #18
SillyUsername wrote: post #6

Earlier quoted context omitted.

Possibly, but in order to be safe for everyone, reviewers may want me to remove features that allow the driver to achieve the non-standard performance. There's a lot of hoops to jump through :)

How did they react to it being vibe coded? Were they pragmatic about it, as Linus recently suggested I have like 4 drivers to upstream myself, plus a couple of patches here and there. Quality is good and they're tested, and while I understand the code and how things work low level, I wouldn't be able to write them myself.

I've never tried it, I am put off by the amount of work for a few weekends on what I considered a personal project, plus I don't understand the code base well enough (problem domain is ok, I grew up with 8 and 16 Bit machines, and pushing graphics driver boundaries in Amiga and VGA monitor era machines). This is why my readme asks for help with issues :)

The dev on this driver used a combination of local Qwen 3.6 and 3.8 27B for admin and basic work, and extensive Codex 5.6 Sol Max to catch the issues I found and do last stage optimisations / isolate the bugs.

I'll freely admit I relied heavily on AI, my expertise and day job is in other software stacks.

I stand on the back of giants :)

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#24

Post by userbinator »

pdpi wrote: post #19
userbinator wrote: post #5

A GPU with HDMI and 16MB of VRAM is a very strange combination.

16 * 1024 * 1024 / 1920 / 1080 = 8.0909, so you have enough VRAM for double-buffered 24-bit 1080p, with a bit to spare. For pure software rendering, that's good enough!

It's the HDMI output that's the oddity; mid-90s cards with that much (little?) VRAM could already do 2048x1536x32, but usually had a VGA connector.

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#25

Post by SillyUsername »

userbinator wrote: post #14
SillyUsername wrote: post #13

Earlier quoted context omitted.

It is just an old school 2D style card, with some (shape) primitives acceleration (unused), two logical controllers (no idea why), but has DMA (used) and a hardware cursor (also used). There's no onboard audio either. It's pretty much a GPU for rack mount servers that require occasional log in. It's exactly what I was looking for desktop work, it runs cinnamon fairly well, and won't clash with my Nvidia setup :)

two logical controllers (no idea why) For dual-monitor versions?

Yes. Stupid comment of mine tbh, I saw it as pointless for this card, but they wouldn't make a separate version of the controller just for this

One avenue I looked at for a real 2560px width was that the second controller was physically independent and could have different hardware limits of the first controller by virtue of supporting DVI directly (but not being physically connected to another port).

Unfortunately other controller is logical so that was a bust.

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#26

Post by SillyUsername »

bigstrat2003 wrote: post #17
SillyUsername wrote: post #2

I wrote* a modern Linux driver that supports ultrawide resolutions, higher refresh, and faster performance than the original driver(s) on this cheap HDMI only variant server GPU. I created it because I wanted my Nvidia GPUs to be compute only, and needed a cheap and small display GPU to run X11. I bought this GPU on AliExpress, after learning it had Linux support. It does, but kernel 5.x series and the sm750 driver i…

[flagged]

I guess this is trolling, but I've never claimed credit for the traditional coding part.

The unique bits I did do

- Checked the specs for actual hardware limits, DMA and any acceleration

- A magic dither based on my previous (normally coded) older projects (see GitHub)

- Image width "compression" idea with loss reduction using sharpening and a slight aspect change.

- Optimising DMA size chunking for optimal memory transfer.

- A lot of actual manual testing, including sheer reduction, frame rate testing, and multiple resolution and different monitor tests (and I lost one - the HDMI port no longer works on my old Celcus)

Failed experiments with:

- using the onboard secondary controller to bypass the primary controller limitations

- devising a hack that would use the vertical scan horizontally using monitor rotation

- attempting an 8, not 16/32 bit desktop for higher performance (old school technique).

- investigating non hardware hacks for overclocking the onboard chips.

- fixing a KVM issue, that required multiple physical disconnects and reconnects to replicate, and a significant amount of weekend time.

So yeah, vibe coded, because I'd never have been able to try these ideas in such a short timescale if I hadn't.

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#27

Post by exe34 »

bigstrat2003 wrote: post #17
SillyUsername wrote: post #2

I wrote* a modern Linux driver that supports ultrawide resolutions, higher refresh, and faster performance than the original driver(s) on this cheap HDMI only variant server GPU. I created it because I wanted my Nvidia GPUs to be compute only, and needed a cheap and small display GPU to run X11. I bought this GPU on AliExpress, after learning it had Linux support. It does, but kernel 5.x series and the sm750 driver i…

[flagged]

I'm assuming your gotcha is going to be "but that's not vibe-coding", but in case you're sincere, you might not have realised this yet: there's a whole range between writing every line by yourself and letting the slop machine create the entire thing. You can rely on your knowledge and understanding to guide it, to the point that it writes code that you would have written, but saves you an enormous amount of time and effort looking up things and creating/running small tests to figure out details. It's a tool, not a spell, so your pearl clutching is a few years out of date...

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#28

Post by pdpi »

userbinator wrote: post #24
pdpi wrote: post #19

Earlier quoted context omitted.

16 * 1024 * 1024 / 1920 / 1080 = 8.0909, so you have enough VRAM for double-buffered 24-bit 1080p, with a bit to spare. For pure software rendering, that's good enough!

It's the HDMI output that's the oddity; mid-90s cards with that much (little?) VRAM could already do 2048x1536x32, but usually had a VGA connector.

Yeah, I could've been clearer.

VGA displays are something of a dying breed, and HDMI is the single likeliest interface you might find on a random newish display, so there is a market for absolute cheapest, most basic HDMI output device you can make. If you're going to build that interface, 1080p is the resolution you need to target. My point was simply that 16MB is just barely enough to build that interface, and barely enough is still enough.

Re: Why open source rocks – a new SM750 (Silicon Motion GPU) HDMI Driver

#30

Post by internet2000 »

SillyUsername wrote: post #2

I wrote* a modern Linux driver that supports ultrawide resolutions, higher refresh, and faster performance than the original driver(s) on this cheap HDMI only variant server GPU. I created it because I wanted my Nvidia GPUs to be compute only, and needed a cheap and small display GPU to run X11. I bought this GPU on AliExpress, after learning it had Linux support. It does, but kernel 5.x series and the sm750 driver i…

Title fix proposal: Why vibecoding rocks
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