Comment by ComputerGuru

Comment by ComputerGuru 8 hours ago

3 replies

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USB doesn’t provide any DMA (until USB 4) and requires more host cpu resources to meet the same bandwidth. It also has less consistent performance by virtue of the USB protocol itself.

mianos 7 hours ago

I am confused by this, I worked on a Linux USB driver that used DMA in 2003.

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  • ComputerGuru 7 hours ago

    DMA from device to host directly rather than from host USB controller to host memory.

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    • mianos 7 hours ago

      When I worked on it, the USB controller was just a pci bus device that once set up, the incoming data, from a USB ADC, streamed the data in blocks directly to memory. Maybe they took all that back out.

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