svn commit: r186903 - head/share/man/man4

[Warner Losh]

Author: imp
Date: Thu Jan  8 15:20:32 2009
New Revision: 186903
URL: http://svn.freebsd.org/changeset/base/186903

Log:
  First cut at documenting hw.cam.cd.retry_count.  Moved
  kern.cam.cd.%d.minimum_cmd_size to new SYSCTL VARIABLES section.

Modified:
  head/share/man/man4/cd.4

Modified: head/share/man/man4/cd.4
==============================================================================
--- head/share/man/man4/cd.4	Thu Jan  8 13:32:08 2009	(r186902)
+++ head/share/man/man4/cd.4	Thu Jan  8 15:20:32 2009	(r186903)
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 2, 2003
+.Dd January 8, 2009
 .Dt CD 4
 .Os
 .Sh NAME
@@ -370,43 +370,6 @@ Some work is planned to support
 some of the more common `broken'
 .Tn CD-ROM
 drives; however, this is not yet under way.
-.Pp
-The
-.Nm
-driver attempts to automatically determine whether the drive it is talking
-to supports 6 byte or 10 byte MODE SENSE/MODE SELECT operations.
-Many
-.Tn SCSI
-drives only support 6 byte commands, and
-.Tn ATAPI
-drives only support 10 byte commands.
-The
-.Nm
-driver first attempts to determine whether the protocol in use typically
-supports 6 byte commands by issuing a CAM Path Inquiry CCB.
-It will then default to 6 byte or 10 byte commands as appropriate.
-After that, the
-.Nm
-driver defaults to using 6 byte commands (assuming the protocol the drive
-speaks claims to support 6 byte commands), until one fails with a
-.Tn SCSI
-ILLEGAL REQUEST error.
-Then it tries the 10 byte version of the command to
-see if that works instead.
-Users can change the default via per-drive
-sysctl variables and loader tunables.
-The variable names are the same in
-both instances:
-.Pp
-.Va kern.cam.cd.%d.minimum_cmd_size
-.Pp
-Where
-.Dq %d
-is the unit number of the drive in question.
-Valid minimum command sizes
-are 6 and 10.
-Any value above 6 will be rounded to 10, and any value below
-6 will be rounded to 6.
 .Sh CHANGER OPERATION
 This driver has built-in support for LUN-based CD changers.
 A LUN-based CD
@@ -466,6 +429,63 @@ probe messages for the various LUNs of t
 while the boot process is going on.
 This is normal, and is caused by the
 changer scheduling code.
+.Sh SYSCTL VARIABLES
+The following variables are available as both
+.Xr sysctl 8
+variables and
+.Xr loader 8
+tunables:
+.Bl -tag -width 12
+.It kern.cam.cd.retry_count
+.Pp
+This variable determines how many times the
+.Nm
+driver will retry a READ or WRITE command.
+This does not affect the number of retries used during probe time or for
+the
+.Nm
+driver dump routine.
+This value currently defaults to 4.
+.It kern.cam.cd.%d.minimum_cmd_size
+.Pp
+The
+.Nm
+driver attempts to automatically determine whether the drive it is talking
+to supports 6 byte or 10 byte MODE SENSE/MODE SELECT operations.
+Many
+.Tn SCSI
+drives only support 6 byte commands, and
+.Tn ATAPI
+drives only support 10 byte commands.
+The
+.Nm
+driver first attempts to determine whether the protocol in use typically
+supports 6 byte commands by issuing a CAM Path Inquiry CCB.
+It will then default to 6 byte or 10 byte commands as appropriate.
+After that, the
+.Nm
+driver defaults to using 6 byte commands (assuming the protocol the drive
+speaks claims to support 6 byte commands), until one fails with a
+.Tn SCSI
+ILLEGAL REQUEST error.
+Then it tries the 10 byte version of the command to
+see if that works instead.
+Users can change the default via per-drive
+sysctl variables and loader tunables.
+Where
+.Dq %d
+is the unit number of the drive in question.
+Valid minimum command sizes
+are 6 and 10.
+Any value above 6 will be rounded to 10, and any value below
+6 will be rounded to 6.
+.It kern.cam.cd.changer.min_busy_seconds
+.It kern.cam.cd.changer.max_busy_seconds
+.Pp
+Tune how long individual LUNs are 'locked' for I/O operations to
+optimize changer operation.
+See CHANGER OPERATION section for information on how to use these items.
+.El
 .Sh FILES
 .Bl -tag -width /dev/cd[0-9][a-h] -compact
 .It Pa /dev/cd[0-9][a-h]