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Comment by geerlingguy | Hacker News Reader

Maybe someone at Arm has sympathy on my plight to get graphics cards running on a Pi—I've had to replace memcpy calls (and memset) to get many parts of the drivers to work at all on arm64.

Note that the Pi also has a not-fully-standard PCIe bus implementation, so that doesn't really help things either.

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If it’s because of having to map the BARs as device memory, then it’s a problem that will be taken care of. That said, the details of the right approach to work around this isn’t quite ironed out yet.

On Apple M1, trying to map the BARs as normal memory directly causes an SError.

As a reminder, the Arm Base System Architecture spec mandates that PCIe BARs must be mappable as normal non-cacheable memory.

I have watched most of your videos on the subject but cannot recall - have you tried running an external GPU on a Nvidia Jetson? Perhaps that is a place to start? (or perhaps I am just letting my ignorance on the matter show)

You mean using the M.2 Key E Slot? Been trying to find a good adaptor for that, any recommendations? (Including nonstandard carrier boards with 8x pcie slots, etc)

If you want to do a bit DIY and go cheap you can but the m.2 to SSF-8643 cards and Dremel a proper keying into it and get a linkreal LRFC6911 for the pcie slot side.

Sounds like a job for Red Shirt Jeff.

That is a possibility, but if you like to do things the easy way there is a full-size PCIe slot on the Xavier AGX dev kit.

Am I nuts or is that like $5000 AUD? The only seller I found with a quick search anyway

Ninja edit: Apparently its $699 USD but it's been scalped by third party sellers. A shame, I'd love to pick one up for some of the work I'm doing!

I am equally disappointed.. Would be surprised, but not verrry, if “people” use this for mining.

EDIT: would you be satisfied with a Jetson Nano combined with the hack mentioned by consp in another comment? (I would be)

Ah right. Was thinking of Nano. As alluded to in the sibling comment, Xaviers seem to be officially out of stock.

Just wanted to say I adore your videos -- and it will be interesting to see where ARM goes in the future to make projects like yours easier (even if only incidentally)

Ill take this opportunity to echo this persons words. Keep the great videos coming.

How come? What is special about how memcpy works compared to a regular load from BAR memory?

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