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Chestnut – eGPU dock with open-source firmware

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41–50 of 54 posts

Re: Chestnut – eGPU dock with open-source firmware

#42
post #28

Earlier quoted context omitted.

I'm surprised that it's pretty much the same as the adapters you can get on aliexpress. Not even a case to protect it from feet in the passenger footwell. Especially compared to the windshield-mount unit, which looks like a very slick product. I suppose they can always improve it if there is interest in this first version.

It’s an incredibly dumb implementation and it feels like yet another case of “AI startup gettin’ while the gettin’s good”. It’s the dotcom bubble all over again. Do anything with AI and people will buy what you’re selling. The RX 9060 has a TDP of 160W, but that’s the high end of what you can continuously draw from the 12v DC plug in a car, so it looks like they cap it at 100W. It has to be on the floor or under the…

wouldn't you also need to worry about the voltage spikes when you're running on battery vs starting the car if you're running an ICE? and would you need to unplug it if you, say, need a jump? feels like you'd also need to install a whole UPS on the other side too if you care about the hardware longevity (not factoring in the sheer amount of dirt/leaves/etc that'll just get caught up in the card itself)

Re: Chestnut – eGPU dock with open-source firmware

#43
post #28

Earlier quoted context omitted.

I'm surprised that it's pretty much the same as the adapters you can get on aliexpress. Not even a case to protect it from feet in the passenger footwell. Especially compared to the windshield-mount unit, which looks like a very slick product. I suppose they can always improve it if there is interest in this first version.

Very much my own opinion, but this continues comma’s extremely cavalier attitude towards safety. PCIe connectors and GPUs are not vibration rated. What happens when you hit a bad pothole?

Soft disengage -- if the GPU fails it continues to drive via on-device model, alerts the user, and then disengages.

More generally, Comma's safety is handled by a microcontroller. The microcontroller limits steering torque commanded to a safe range for level 2 driver assistance and acts as a watchdog for the rest of the stack. Failure of openpilot causes it to disengage and sound an audible alarm.

Re: Chestnut – eGPU dock with open-source firmware

#45

This bridge - does it actually support host PCIe->thunderbolt->PCIe device - my reading of it is that it's just handling USB commands that the bridge is turning into separate PCIe commands to the GPU?

My understanding is both USB 4 and TB use PCIe tunneling. Surely at this price point we’re looking at a USB 4 device. Thunderbolt has historically cost more due to licensing, which is now free I believe, but there’s still specialized hardware and requirements manufacturers need to adhere to.

Re: Chestnut – eGPU dock with open-source firmware

#47
post #4

Earlier quoted context omitted.

If you liked that, you should look into tinygrad

If you're like me and also wondered "huh, what's tinygrad up to?" apparently they now let you place $100,000 USD pre-orders on a $10M shipping container full of GPUs which they say will ship (literally it seems) in 2027.

Are they planning to do something like runware with their containers? ( Sonic inference pod)

Re: Chestnut – eGPU dock with open-source firmware

#48
post #5

Huh intersting that that they don't support any of the european Stellantis brands at all, wonder what they do differently that makes them incompatible.

I’m working on integrating with a Jeep Renegade which was designed on the Fiat small-wide platform, and the CAN bus architecture is a non-starter for mainline OpenPilot support. OpenPilot requires every signal needed from/to the car is accessible by tapping at most two CAN buses, both of which must be accessible on the cable to the lane assist camera behind the rear view mirror.

On the Renegade, the adaptive cruise control activation and control signals are on a separate bus from the steering control signals, and the ACC signals don’t get up to the lane assist camera at all. OpenPilot support on this vehicle will require tapping CAN buses in two spots on the vehicle, and this is not a Comma-supported configuration. They want to be able to make a single interposer cable that plugs in between the lane assist camera and your car, and if that’s not possible they will never support your vehicle.

To attempt to support my car I am working on a gateway device that will bridge information from the powertrain bus to the fusion bus so it will be available at the camera (which is on the fusion bus and the chassis bus). But this implementation, which may not actually work but even if it does, will never be accepted upstream. And safety-wise, that’s probably the right choice for the project.

The sad part is I think the only signal that I need that I don’t have at the camera right now to make a safe implementation is ACC engagement. I’ve scrutinized every bit of every message on the chassis and fusion buses available at the camera and there is simply no signal that indicates if ACC is engaged.

One bit is all I need to get lateral control working. Well, assuming that once I start injecting control signals there aren’t other issues, that is. And that is not probably a safe assumption.

Re: Chestnut – eGPU dock with open-source firmware

#49
post #5

Huh intersting that that they don't support any of the european Stellantis brands at all, wonder what they do differently that makes them incompatible.

I’m working on integrating with a Jeep Renegade which was designed on the Fiat small-wide platform, and the CAN bus architecture is a non-starter for mainline OpenPilot support. OpenPilot requires every signal needed from/to the car is accessible by tapping at most two CAN buses, both of which must be accessible on the cable to the lane assist camera behind the rear view mirror. On the Renegade, the adaptive cruise c…

Thanks for the insider knowledge, very interesting!

I really think to buy my next car which is supported by comma

Re: Chestnut – eGPU dock with open-source firmware

#50

Two things: 1. they have a cheap fuse (cents on the dollar) that’s not automotive-grade so your windshield mounted device fails in hot weather and doesn’t last past the hardware warranty. Known issue, doubt they ever fixed it. 2. 1B parameter model to stay between two lines. Why. Waste of time. Their product hasn’t actually changed in several years because they will never advance past lane keeping SAE Level 2. I susp…

You're not paying $1,000 for a cut down Android when you buy a Comma Four. What you're buying is an entry ticket to Comma-land — where dozens of car models are supported, pre-made harnesses are just a buy button away, and everything is open source. If George had chosen to go the closed source route, you might be paying $200 for a locked-down device and $200 every month for a mandatory subscription. Which one makes yo…

I want them to improve the product meaningfully beyond lane keeping, which besides lane changing (partially), it's the only thing it's capable of because they willingly choose not to extend the system to use more visibility.
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