[src/trunk]: src/sys/dev/ic If we are using UDMA mode > 2 and get a DMA error...

[bouyer <bouyer%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/737a77b65b9e
branches:  trunk
changeset: 475940:737a77b65b9e
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Mon Aug 30 12:58:58 1999 +0000

description:
If we are using UDMA mode > 2 and get a DMA error, downgrade to UDMA mode 2
first: maybe we incorrectly guessed the cable type.

diffstat:

 sys/dev/ic/wdc.c |  14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diffs (34 lines):

diff -r dfdc3d5e30bf -r 737a77b65b9e sys/dev/ic/wdc.c
--- a/sys/dev/ic/wdc.c  Mon Aug 30 12:49:21 1999 +0000
+++ b/sys/dev/ic/wdc.c  Mon Aug 30 12:58:58 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: wdc.c,v 1.72 1999/08/25 17:08:20 bouyer Exp $ */
+/*     $NetBSD: wdc.c,v 1.73 1999/08/30 12:58:58 bouyer Exp $ */
 
 
 /*
@@ -988,13 +988,23 @@
                return 0;
 
        /*
+        * If we were using Ultra-DMA mode > 2, downgrade to mode 2 first.
+        * Maybe we didn't properly notice the cable type
+        */
+       if ((drvp->drive_flags & DRIVE_UDMA) && drvp->UDMA_mode > 2) {
+               drvp->UDMA_mode = 2;
+               printf("%s: transfer error, downgrading to DMA mode %d\n",
+                   drv_dev->dv_xname, drvp->UDMA_mode);
+       }
+
+       /*
         * If we were using ultra-DMA, don't downgrade to multiword DMA
         * if we noticed a CRC error. It has been noticed that CRC errors
         * in ultra-DMA lead to silent data corruption in multiword DMA.
         * Data corruption is less likely to occur in PIO mode.
         */
 
-       if ((drvp->drive_flags & DRIVE_UDMA) &&
+       else if ((drvp->drive_flags & DRIVE_UDMA) &&
            (drvp->drive_flags & DRIVE_DMAERR) == 0) {
                drvp->drive_flags &= ~DRIVE_UDMA;
                drvp->drive_flags |= DRIVE_DMA;