staging: comedi: das16: fix DMA size for short transfers

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Currently this driver alwasy programs the DMA transfer to be the allocated
size of the DMA buffer. When the async command 'stop_src' is TRIG_COUNT its
possible (likely) for the last transfer to be less than the buffer size.

Introduce a helper function, das16_ai_setup_dma(), to calculate the actual
size of the DMA transfer based on the number of samples remaining and the
number of unread samples.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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H Hartley Sweeten 2015-01-26 16:17:20 -07:00 • committed by Greg Kroah-Hartman

parent 42c44682a5

commit 1dc6e72903

1 changed files with 25 additions and 9 deletions

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drivers/staging/comedi/drivers/das16.c

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