Here is a patch to alleviate the current problem with the dma interface

and the sound driver which uses auto dma.

The  dma interface functionality remains however it now checks
to see if a dma is operating in auto dma mode and if so it bypasses
the busy flag check . I have modified the sound driver 3.5  to
adjust for this new behavior and tested it under FreeBSD 3.0 -current

This patch also includes the new function isa_dmastop.

Submitted by:	Amancio Hasty <hasty@rah.star-gate.com>

1 files changed, 42 insertions, 14 deletions

diff --git a/sys/i386/isa/isa.c b/sys/i386/isa/isa.c
index 0b6fe36..abdcfa3 100644
--- a/sys/i386/isa/isa.c
+++ b/sys/i386/isa/isa.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)isa.c	7.2 (Berkeley) 5/13/91
- *	$Id: isa.c,v 1.101 1997/08/21 05:08:07 fsmp Exp $
+ *	$Id: isa.c,v 1.102 1997/08/25 22:52:59 bde Exp $
  */
 
 /*
@@ -573,6 +573,7 @@ static u_int	dma_bouncebufsize[8];
 static u_int8_t	dma_bounced = 0;
 static u_int8_t	dma_busy = 0;		/* Used in isa_dmastart() */
 static u_int8_t	dma_inuse = 0;		/* User for acquire/release */
+static u_int8_t dma_auto_mode = 0;
 
 #define VALID_DMA_MASK (7)
 
@@ -634,6 +635,7 @@ isa_dma_acquire(chan)
 		return (EBUSY);
 	}
 	dma_inuse |= (1 << chan);
+	dma_auto_mode &= ~(1 << chan);
 
 	return (0);
 }
@@ -665,6 +667,7 @@ isa_dma_release(chan)
 	}
 
 	dma_inuse &= ~(1 << chan);
+	dma_auto_mode &= ~(1 << chan);
 }
 
 /*
@@ -739,6 +742,12 @@ void isa_dmastart(int flags, caddr_t addr, u_int nbytes, int chan)
 	/* translate to physical */
 	phys = pmap_extract(pmap_kernel(), (vm_offset_t)addr);
 
+	if (flags & B_RAW) {
+	    dma_auto_mode |= (1 << chan);
+	} else { 
+	    dma_auto_mode &= ~(1 << chan);
+	}
+
 	if ((chan & 4) == 0) {
 		/*
 		 * Program one of DMA channels 0..3.  These are
@@ -819,15 +828,10 @@ void isa_dmadone(int flags, caddr_t addr, int nbytes, int chan)
 		printf("isa_dmadone: channel %d not acquired\n", chan);
 #endif
 
-#if 0
-	/*
-	 * XXX This should be checked, but drivers like ad1848 only call
-	 * isa_dmastart() once because they use Auto DMA mode.  If we
-	 * leave this in, drivers that do this will print this continuously.
-	 */
-	if ((dma_busy & (1 << chan)) == 0)
+	if (((dma_busy & (1 << chan)) == 0) && 
+	    (dma_auto_mode & (1 << chan)) == 0 )
 		printf("isa_dmadone: channel %d not busy\n", chan);
-#endif
+
 
 	if (dma_bounced & (1 << chan)) {
 		/* copy bounce buffer on read */
@@ -916,12 +920,13 @@ isa_dmastatus(int chan)
 		printf("isa_dmastatus: channel %d not active\n", chan);
 		return(-1);
 	}
+	/* channel busy? */
 
-	/* still busy? */
-	if ((dma_busy & (1 << chan)) == 0) {
-		return(0);
-	}
-	
+	if (((dma_busy & (1 << chan)) == 0) &&
+	    (dma_auto_mode & (1 << chan)) == 0 ) {
+	    printf("chan %d not busy\n", chan);
+	    return -2 ;
+	}	
 	if (chan < 4) {			/* low DMA controller */
 		ffport = DMA1_FFC;
 		waport = DMA1_CHN(chan) + 1;
@@ -956,6 +961,29 @@ isa_dmastatus(int chan)
 }
 
 /*
+ * Stop a DMA transfer currently in progress.
+ */
+int
+isa_dmastop(int chan) 
+{
+	if ((dma_inuse & (1 << chan)) == 0)
+		printf("isa_dmastop: channel %d not acquired\n", chan);  
+
+	if (((dma_busy & (1 << chan)) == 0) &&
+	    ((dma_auto_mode & (1 << chan)) == 0)) {
+		printf("chan %d not busy\n", chan);
+		return -2 ;
+	}
+    
+	if ((chan & 4) == 0) {
+		outb(DMA1_SMSK, (chan & 3) | 4 /* disable mask */);
+	} else {
+		outb(DMA2_SMSK, (chan & 3) | 4 /* disable mask */);
+	}
+	return(isa_dmastatus(chan));
+}
+
+/*
  * Find the highest priority enabled display device.  Since we can't
  * distinguish display devices from ttys, depend on display devices
  * being sensitive and before sensitive non-display devices (if any)