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staging: comedi: pcl812: fix logic error in pcl812_ai_setup_dma()

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commit 92afc2b229 inroduced a logic error
in the DMA size calculation.

If the 'nsamples' is greater than the 'unread_samples' then DMA needs to
be restarted. The current code checks it agains the 'max_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>
This commit is contained in:
H Hartley Sweeten 2015-01-26 14:20:15 -07:00 committed by Greg Kroah-Hartman
parent 119c964399
commit fd27ae76d2
1 changed files with 2 additions and 2 deletions
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4
drivers/staging/comedi/drivers/pcl812.c
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@ -559,8 +559,8 @@ static void pcl812_ai_setup_dma(struct comedi_device *dev,
* unread samples and the number of samples remaining in the command.
*/
nsamples = comedi_nsamples_left(s, max_samples + unread_samples);
if (nsamples > max_samples) {
nsamples -= max_samples;
if (nsamples > unread_samples) {
nsamples -= unread_samples;
desc->size = comedi_samples_to_bytes(s, nsamples);
comedi_isadma_program(desc);
}