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AM3358: Failed data transfer of 15MBytes/sec over USB using BBB.

Vikas Dubey
Intellectual 390 points
Part Number: AM3358

Hi,

Currently I trying to capture to capture 1MB  MJPEG frames with 15Frames/sec  and read over USB.

Upto 700KB frames no issue with frame read, but after that frames are getting corrupted.

Increased CPU speed to 1GHz, but no help.

I am doubting USB read has its limitation for BBB(Read from one of TI community reply, to be ~13.3MB/s). I need to enhance it. Please guide.

I am using latest TI SDK.

Best Regards,

Vikas

  • 0
    TI__Mastermind 30506 points
    Vikas,

    Thank you for your post. Our expert on this is out this week and will reply next week when he returns. I'm sorry for the delay.
  • 0
    TI__Guru**** 167581 points
    Hi Vikas,

    Sorry for my late response.

    Based on your description that testing on 700KB@15fps passed, but 1MB@15fps failed, it appears you face the usb throughput limit in the current kernel for AM3358. Based on my analysis the problem is that the kernel usb-v4l2 layer takes too long time to process each video frame while holding a kernel spinlock which disables hw (the usb controller in this case) interrupts. I have tried to work with the kernel open source community trying to solve the issue, but didn't find a solution yet.

    Currently we don't have a timeline when the issue could be solved.