Date: Thu, 8 Jan 2009 15:20:32 +0000 (UTC) From: Warner Losh <imp@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r186903 - head/share/man/man4 Message-ID: <200901081520.n08FKWDG025879@svn.freebsd.org>
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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]
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