First cut at documenting hw.cam.cd.retry_count. Moved

kern.cam.cd.%d.minimum_cmd_size to new SYSCTL VARIABLES section.

1 files changed, 58 insertions, 38 deletions

diff --git a/share/man/man4/cd.4 b/share/man/man4/cd.4
index 19113b7..ec16751 100644
--- a/share/man/man4/cd.4
+++ b/share/man/man4/cd.4
@@ -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 the changer will continue to appear
 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]