From 27c97f766064c33d3a0cb80d7ceaa82de6682058 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dag-Erling=20Sm=C3=B8rgrav?= <des@FreeBSD.org>
Date: Wed, 24 Oct 2001 18:24:09 +0000
Subject: [PATCH] Don't enable write cacheing on devices that don't support
 tagged queuing unless hw.ata.wc is set.

Approved by:	sos
MFC after:	1 week
---
 sys/dev/ata/ata-disk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/ata/ata-disk.c b/sys/dev/ata/ata-disk.c
index d9f662f305ab..e7117158602f 100644
--- a/sys/dev/ata/ata-disk.c
+++ b/sys/dev/ata/ata-disk.c
@@ -158,7 +158,7 @@ ad_attach(struct ata_softc *scp, int device)
 	ata_printf(scp, device, "enabling readahead cache failed\n");
 
     /* enable write cacheing if allowed and not default on device */
-    if (ata_wc || ata_tags) {
+    if (ata_wc || (ata_tags && ad_tagsupported(adp))) {
 	if (ata_command(adp->controller, adp->unit, ATA_C_SETFEATURES,
 			0, 0, ATA_C_F_ENAB_WCACHE, ATA_WAIT_INTR))
 	    ata_printf(scp, device, "enabling write cache failed\n");