DMA Userbuffer

Hi all,

I’m writing a driver for a device
using a plx9080 chip. I’ve implemented
scatter gather DMA.

However when I open the memory mapped
file representing the user buffer I
get a bunch of FF’s.

I’m sure that:

  • The hardware input doesn’t contain the FF’s
  • The transfer works because I get the exact amount
    of data I requested. (Tested both 32KB/64KB requests)

Is there a way to see the internal FIFO? Any other
things that could be wrong?

Thanks in advance,

Kind regards,

Roy