> Now the curiousity; if we use a pointer to the data area as returned
> from request_firmware, it doesn't work. If, however, we use the stack
> (or a kmalloc'ed area) and copy over and pass the stack (or km'ed area)
> address, then it works.
> Only thing I could find is that request_firmware allocates the data area
> using vmalloc. Why is this a problem ?
Because vmalloced memory isn't physically contiguous and hence cannot
be DMAed in one go. You need to walk the page tables like the usb video
drivers do, or build a scatter/gather table for the _sg_ usb api functions.
Regards
Oliver
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