Some revisions of the aic7880 have a problem where, if the

data fifo is full, but the PCI input latch is not empty,
HDMAEN cannot be cleared.  The fix used here is to attempt
to drain the data fifo until there is space for the input
latch to drain and HDMAEN de-asserts.

This is a 1 instruction fix, so it should have no performance
impact.

1 files changed, 10 insertions, 2 deletions

diff --git a/sys/dev/aic7xxx/aic7xxx.seq b/sys/dev/aic7xxx/aic7xxx.seq
index d7338a5..f3fad03 100644
--- a/sys/dev/aic7xxx/aic7xxx.seq
+++ b/sys/dev/aic7xxx/aic7xxx.seq
@@ -35,7 +35,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: aic7xxx.seq,v 1.75 1997/08/13 17:02:28 gibbs Exp $
+ *	$Id: aic7xxx.seq,v 1.76 1997/09/27 19:37:27 gibbs Exp $
  */
 
 #include <dev/aic7xxx/aic7xxx.reg>
@@ -944,7 +944,15 @@ dma_fifoempty:
 dma_dmadone:
 	and	DFCNTRL, ~(SCSIEN|SDMAEN|HDMAEN);
 dma_halt:
-	test	DFCNTRL, (SCSIEN|SDMAEN|HDMAEN)	jnz dma_halt; 
+	/*
+	 * Some revisions of the aic7880 have a problem where, if the
+	 * data fifo is full, but the PCI input latch is not empty, 
+	 * HDMAEN cannot be cleared.  The fix used here is to attempt
+	 * to drain the data fifo until there is space for the input
+	 * latch to drain and HDMAEN de-asserts.
+	 */
+	mov	NONE, DFDAT;
+	test	DFCNTRL, HDMAEN jnz dma_halt;
 return:
 	ret;