MFC: 212624, 212669, 213535

MFC: 212624, 212669, 213535

Merge the mps(4) man page.

  r212624 | ken | 2010-09-14 15:40:29 -0600 (Tue, 14 Sep 2010) | 7 lines

  MFp4 (//depot/projects/mps/...)

  Add a man page for the mps(4) driver, and reference it in the
  mpt(4) driver man page.

  Sponsored by:   Spectra Logic Corporation

  r212669 | ken | 2010-09-15 10:05:51 -0600 (Wed, 15 Sep 2010) | 6 lines

  MFp4 (//depot/projects/mps/...)

  Fix a typo.

  Submitted by:   pluknet at gmail dot com

  r213535 | ken | 2010-10-07 15:56:10 -0600 (Thu, 07 Oct 2010) | 36 lines

  Turn on serialization of task management commands going down to the
  controller, but make it optional.

  After a problem report from Andrew Boyer, it looks like the LSI
  chip may have issues (the watchdog timer fired) if too many aborts
  are sent down to the chip at the same time.  We know that task
  management commands are serialized, and although the manual doesn't
  say it, it may be a good idea to just send one at a time.

  But, since I'm not certain that this is necessary, add a tunable
  and sysctl variable (hw.mps.%d.allow_multiple_tm_cmds) to control
  the driver's behavior.

  mps.c:		Add support for the sysctl and tunable, and add a
  		comment about the possible return values to
  		mps_map_command().

  mps_sas.c:	Run all task management commands through two new
  		routines, mpssas_issue_tm_request() and
  		mpssas_complete_tm_request().

  		This allows us to optionally serialize task
  		management commands.  Also, change things so that
  		the response to a task management command always
  		comes back through the callback.  (Before it could
  		come via the callback or the return value.)

  mpsvar.h:	Add softc variables for the list of active task
  		management commands, the number of active commands,
  		and whether we should allow multiple active task
  		management commands.  Add an active command flag.

  mps.4:		Describe the new sysctl/loader tunable variable.

  Sponsored by:   Spectra Logic Corporation

Reminded by:	Hubert Tournier <hubert at frbsd dot org>

git-svn-id: svn://svn.freebsd.org/base/stable/8@219678 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f