When setting up the DMA for 'read' streaming acquisition on the DIO subdevice, mark the whole buffer as writable before starting the DMA. This prevents a spurious detection of a DMA overwrite of good data during the first interrupt.
Problem reported by Nicholas Nell. Fix suggested by Frank Mori Hess. Signed-off-by: Ian Abbott <[email protected]> --- drivers/staging/comedi/drivers/ni_pcidio.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/staging/comedi/drivers/ni_pcidio.c b/drivers/staging/comedi/drivers/ni_pcidio.c index 045a4c0..c9e5f2b 100644 --- a/drivers/staging/comedi/drivers/ni_pcidio.c +++ b/drivers/staging/comedi/drivers/ni_pcidio.c @@ -1012,6 +1012,9 @@ static int setup_mite_dma(struct comedi_device *dev, struct comedi_subdevice *s) devpriv->di_mite_chan->dir = COMEDI_INPUT; + /* write alloc the entire buffer */ + comedi_buf_write_alloc(s->async, s->async->prealloc_bufsz); + mite_prep_dma(devpriv->di_mite_chan, 32, 32); mite_dma_arm(devpriv->di_mite_chan); -- 1.7.8.2 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
