From 41add2e84bff0c887949698e01dab28105f11a6b Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Mon, 9 Jan 2012 15:47:30 +0000 Subject: [PATCH] staging: comedi: ni_pcidio: Mark buffer for writing when setting up DMA. 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 Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/ni_pcidio.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/staging/comedi/drivers/ni_pcidio.c b/drivers/staging/comedi/drivers/ni_pcidio.c index 045a4c00f346..c9e5f2b2dfbb 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); -- 2.11.0