From ea6ecb4e52f87d3c46d35f55326b14ecf678c405 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20E=C3=9Fer?= <se@FreeBSD.org>
Date: Thu, 2 Feb 1995 15:50:57 +0000
Subject: [PATCH] Disable disconnect after drive timeouts, since these may be
 the result of reselect following too fast for the driver to notice. Not the
 final solution, but the problem has been seen only with very few devices.

Reviewed by:	se
Submitted by:	wolf (Wolfgang Stanglmeier)
---
 sys/pci/ncr.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/sys/pci/ncr.c b/sys/pci/ncr.c
index d21664c3761..f9cd370d2fb 100644
--- a/sys/pci/ncr.c
+++ b/sys/pci/ncr.c
@@ -1,6 +1,6 @@
 /**************************************************************************
 **
-**  $Id: ncr.c,v 1.15 1995/02/02 12:36:16 davidg Exp $
+**  $Id: ncr.c,v 1.16 1995/02/02 13:12:15 davidg Exp $
 **
 **  Device driver for the   NCR 53C810   PCI-SCSI-Controller.
 **
@@ -44,7 +44,7 @@
 ***************************************************************************
 */
 
-#define	NCR_PATCHLEVEL	"pl4 95/01/27"
+#define	NCR_PATCHLEVEL	"pl6 95/02/02"
 
 #define NCR_VERSION	(2)
 #define	MAX_UNITS	(16)
@@ -1073,6 +1073,11 @@ struct ncb {
 	*/
 	u_char		maxwide;
 
+	/*
+	**	option for M_IDENTIFY message: enables disconnecting
+	*/
+	u_char		disc;
+
 	/*
 	**	lockout of execption handler call while starting command.
 	*/
@@ -1226,7 +1231,7 @@ static	void	ncr_attach	(pcici_t tag, int unit);
 
 
 static char ident[] =
-	"\n$Id: ncr.c,v 1.15 1995/02/02 12:36:16 davidg Exp $\n";
+	"\n$Id: ncr.c,v 1.16 1995/02/02 13:12:15 davidg Exp $\n";
 
 u_long	ncr_version = NCR_VERSION
 	+ (u_long) sizeof (struct ncb)
@@ -3352,8 +3357,10 @@ static	void ncr_attach (pcici_t config_id, int unit)
 	/*
 	**	process the reset exception,
 	**	if interrupts are not enabled yet.
+	**	than enable disconnects.
 	*/
 	ncr_exception (np);
+	np->disc = 1;
 
 #ifdef ANCIENT
 	printf ("%s: waiting for scsi devices to settle\n",
@@ -3699,21 +3706,19 @@ static INT32 ncr_start (struct scsi_xfer * xp)
 	**----------------------------------------------------
 	*/
 
+	idmsg = M_IDENTIFY | xp->LUN;
 #ifndef NCR_NO_DISCONNECT
-	idmsg = (cp==&np->ccb ? M_IDENTIFY : 0xc0) | xp->LUN;
-#else
 	/*---------------------------------------------------------------------
 	** Some users have problems with this driver.
 	** I assume that the current problems relate to a conflict between
 	** a disconnect and an immediately following reconnect operation.
-	** With this option you can prevent the driver from using disconnects.
-	** If this removes the problems, I would know where to search further..
-	** Of course this is no solution.
+	** With this option one can prevent the driver from using disconnects.
 	** Without disconnects the performance will be severely degraded.
 	** But it may help to trace down the core problem.
 	**---------------------------------------------------------------------
 	*/
-	idmsg = M_IDENTIFY | xp->LUN;
+	if ((cp!=&np->ccb) && (np->disc))
+		idmsg |= 0x40;
 #endif
 
 	cp -> scsi_smsg [0] = idmsg;
@@ -4381,6 +4386,12 @@ void ncr_init (ncb_p np, char * msg, u_long code)
 	usrwide = (SCSI_NCR_MAX_WIDE);
 	if (usrwide > np->maxwide) usrwide=np->maxwide;
 
+	/*
+	**	Disable disconnects.
+	*/
+
+	np->disc = 0;
+
 	/*
 	**	Fill in target structure.
 	*/