The DMA operations used by the driver may have been set up to acquire
data from unwanted channels in addition to the wanted channels.
Currently, `interrupt_pci9118_ai_dma()` calls `defragment_dma_buffer()`
to move all the wanted data to the start of the DMA buffer and then
calls `comedi_buf_write_samples()` to copy it all to the comedi async
buffer. Those two functions used to be called from
`move_block_from_dma()` which was absorbed into
`interrupt_pci9118_ai_dma()`.
Reinstate `move_block_from_dma()` but rewrite it to copy data directly
from the wanted fragments of the DMA buffer to the comedi async buffer
without defragmenting the buffer first.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
e87f65b238