Allocate DMA bounce buffers only when requested by drivers. Only the

fd and wt drivers need bounce buffers, so this normally saves 32K-1K
of kernel memory.

Keep track of which DMA channels are busy.  isa_dmadone() must now be
called when DMA has finished or been aborted.

Panic for unallocated and too-small (required) bounce buffers.

fd.c:
There will be new warnings about isa_dmadone() not being called after
DMA has been aborted.

sound/dmabuf.c:
isa_dmadone() needs more parameters than are available, so temporarily
use a new interface isa_dmadone_nobounce() to avoid having to worry
about panics for fake parameters.  Untested.

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/i386/isa/wt.c b/sys/i386/isa/wt.c
index 08e49f9..f571e46 100644
--- a/sys/i386/isa/wt.c
+++ b/sys/i386/isa/wt.c
@@ -19,7 +19,7 @@
  * the original CMU copyright notice.
  *
  * Version 1.3, Thu Nov 11 12:09:13 MSK 1993
- * $Id: wt.c,v 1.27 1995/12/22 15:39:45 bde Exp $
+ * $Id: wt.c,v 1.28 1996/01/08 12:46:14 joerg Exp $
  *
  */
 
@@ -293,6 +293,7 @@ wtattach (struct isa_device *id)
 	t->flags = TPSTART;                     /* tape is rewound */
 	t->dens = -1;                           /* unknown density */
 	kdc_wt[id->id_unit].kdc_state = DC_IDLE;
+	isa_dmainit(t->chan, 1024);
 
 #ifdef DEVFS
 	sprintf(name,"rwt%d",id->id_unit);