apply dma init fix that worked so well with cb_pcidas64.c

diff --git a/comedi/drivers/gsc_hpdi.c b/comedi/drivers/gsc_hpdi.c
index ce681f169331568876263191d7788241a981daae..071f9b5026efb022eec451a58f32630bce7cf442 100644 (file)
--- a/comedi/drivers/gsc_hpdi.c
+++ b/comedi/drivers/gsc_hpdi.c
@@ -818,6 +818,13 @@ static int di_cmd(comedi_device *dev,comedi_subdevice *s)
 
        priv(dev)->dma_desc_index = 0;
 
+       /* These register are supposedly unused during chained dma,
+       * but I have found that left over values from last operation
+       * occasionally cause problems with transfer of first dma
+       * block.  Initializing them to zero seems to fix the problem. */
+       writel(0, priv(dev)->plx9080_iobase + PLX_DMA0_TRANSFER_SIZE_REG);
+       writel(0, priv(dev)->plx9080_iobase + PLX_DMA0_PCI_ADDRESS_REG);
+       writel(0, priv(dev)->plx9080_iobase + PLX_DMA0_LOCAL_ADDRESS_REG);
        // give location of first dma descriptor
        bits = priv(dev)->dma_desc_phys_addr | PLX_DESC_IN_PCI_BIT | PLX_INTR_TERM_COUNT | PLX_XFER_LOCAL_TO_PCI;
        writel( bits, priv(dev)->plx9080_iobase + PLX_DMA0_DESCRIPTOR_REG );