svn commit: r231745 - head/sys/cam/scsi

[Justin T. Gibbs]

Author: gibbs
Date: Wed Feb 15 07:30:23 2012
New Revision: 231745
URL: http://svn.freebsd.org/changeset/base/231745

Log:
  Limit the ST3146855LW U320 drive to 55 tags to avoid command timeouts
  under load.
  
  Submitted by:	Gelson Borsoi
  MFC after:	1 day

Modified:
  head/sys/cam/scsi/scsi_xpt.c

Modified: head/sys/cam/scsi/scsi_xpt.c
==============================================================================
--- head/sys/cam/scsi/scsi_xpt.c	Wed Feb 15 06:49:50 2012	(r231744)
+++ head/sys/cam/scsi/scsi_xpt.c	Wed Feb 15 07:30:23 2012	(r231745)
@@ -295,6 +295,14 @@ static struct scsi_quirk_entry scsi_quir
 	},
 	{
 		/*
+		 * Experiences command timeouts under load with a
+		 * tag count higher than 55.
+		 */
+		{ T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST3146855LW", "*"},
+		/*quirks*/0, /*mintags*/2, /*maxtags*/55
+	},
+	{
+		/*
 		 * Slow when tagged queueing is enabled.  Write performance
 		 * steadily drops off with more and more concurrent
 		 * transactions.  Best sequential write performance with