From owner-freebsd-stable  Mon Apr 10  2:44:32 2000
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Date: Mon, 10 Apr 2000 03:11:00 -0700
From: Alfred Perlstein <bright@wintelcom.net>
To: msmith@freebsd.org
Cc: stable@freebsd.org
Subject: Mini amr MFC?
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Mike, I've been really busy over here with a _lot_ of things. :)

Anyhow, I wasn't able to follow the entire thread about resolving
the lockups with the amr driver (I was getting lockups as well).

The gist I got from what I was able to skim was that the deciding
change that made it stable was simply limiting the commands to
AMR_LIMITCMD (120).

Anyhow, here's a diff, I plan to commit it asap if my box survives
a cvs up off a local repo after patching, or would that not solve
the problem in RELENG_4?


Index: amr.c
===================================================================
RCS file: /home/ncvs/src/sys/dev/amr/amr.c,v
retrieving revision 1.7
diff -u -r1.7 amr.c
--- amr.c	2000/02/17 23:33:57	1.7
+++ amr.c	2000/04/10 09:35:47
@@ -698,7 +698,11 @@
 			  ae->ae_adapter.aa_memorysize);
 	}
 	sc->amr_maxdrives = 8;
-	sc->amr_maxio = ae->ae_adapter.aa_maxio;
+	/*
+	 * Cap the maximum number of outstanding I/Os.  AMI's Linux driver doesn't trust
+	 * the controller's reported value, and lockups have been seen when we do.
+	 */
+	sc->amr_maxio = imin(ae->ae_adapter.aa_maxio, AMR_LIMITCMD);
 	for (i = 0; i < ae->ae_ldrv.al_numdrives; i++) {
 	    sc->amr_drive[i].al_size = ae->ae_ldrv.al_size[i];
 	    sc->amr_drive[i].al_state = ae->ae_ldrv.al_state[i];
Index: amrvar.h
===================================================================
RCS file: /home/ncvs/src/sys/dev/amr/amrvar.h,v
retrieving revision 1.2
diff -u -r1.2 amrvar.h
--- amrvar.h	1999/10/26 23:18:57	1.2
+++ amrvar.h	2000/04/10 09:34:28
@@ -38,6 +38,7 @@
 #define AMR_SIGNATURE	0x3344
 
 #define AMR_MAXCMD	255		/* ident = 0 not allowed */
+#define AMR_LIMITCMD	120
 #define AMR_MAXLD      	40
 
 #define AMR_BLKSIZE	512


-- 
-Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
"I have the heart of a child; I keep it in a jar on my desk."


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