From: Ian Abbott Date: Mon, 9 Jan 2012 15:47:30 +0000 (+0000) Subject: staging: comedi: ni_pcidio: Mark buffer for writing when setting up DMA. X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=41add2e84bff0c887949698e01dab28105f11a6b;p=mv-sheeva.git 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 --- diff --git a/drivers/staging/comedi/drivers/ni_pcidio.c b/drivers/staging/comedi/drivers/ni_pcidio.c index 045a4c00f34..c9e5f2b2dfb 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);