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
When the driver is completely saturated with commands (1024 in the
case of the SAS2008 in my test system), I/O stops. If we tell CAM
that we have one less command slot than we have actually allocated,
everything works fine. We also need a few extra command slots to
allow for aborts and other task management commands to be sent down.
This needs more investigation to determine the root cause, but for
now this fixes things in my testing.
mps.c: Change a printf() to mps_printf().
mps_sas.c: Subtract 5 command slots when we tell CAM how many
commands we can handle.
Add some commented-out logic to print the contents
the CDBs for timed-out commands. This can help
in debugging devices that are timing out. This
will be uncommented once I bring some CAM changes in.
Reported by: Andrew Boyer <aboyer at averesystems dot com>
According to the MPT2 spec, task management commands are
serialized, and so no I/O should start while task management
commands are active.
So, to comply with that, freeze the SIM queue before we send any
task management commands (abort, target reset, etc.) down to the
IOC. We unfreeze the queue once the task management command
completes.
It isn't clear from the spec whether multiple simultaneous task
management commands are supported. Right now it is possible to
have multiple outstanding task management commands, especially in
the abort case. Multiple outstanding aborts do complete
successfully, so it may be supported.
We also don't yet have any recovery mechanism (e.g. reset the IOC)
if the task management command fails.
Bring in a driver for the LSI Logic MPT2 6Gb SAS controllers.
This driver supports basic I/O, and works with SAS and SATA drives and
expanders.
Basic error recovery works (i.e. timeouts and aborts) as well.
Integrated RAID isn't supported yet, and there are some known bugs.
So this isn't ready for production use, but is certainly ready for
testing and additional development. For the moment, new commits to this
driver should go into the FreeBSD Perforce repository first
(//depot/projects/mps/...) and then get merged into -current once
they've been vetted.
This has only been added to the amd64 GENERIC, since that is the only
architecture I have tested this driver with.
Submitted by: scottl
Discussed with: imp, gibbs, will
Sponsored by: Yahoo, Spectra Logic Corporation
