.\" Copyright (c) 2014 LSI Corp
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.\" Author: Kashyap Desai
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.\" $FreeBSD$
.\"
.Dd May 8, 2014
.Dt MRSAS 4
.Os
.Sh NAME
.Nm mrsas
.Nd "LSI MegaRAID 6Gb/s and 12Gb/s SAS+SATA RAID controller driver"
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device pci"
.Cd "device mrsas"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
mrsas_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm 
driver will detect LSI's next generation (6Gb/s and 12Gb/s) PCI Express
SAS/SATA RAID controllers.
See the
.Nm HARDWARE
section for the supported devices list.
A disk (virtual disk/physical disk) attached to the 
.Nm
driver will be visible to the user through 
.Xr camcontrol 8
as
.Pa /dev/da?
device nodes.
A simple management interface is also provided on a per-controller basis via the
.Pa /dev/mrsas?
device node.
.Pp
The
.Nm
name is derived from the phrase "MegaRAID SAS HBA", which is
substantially different than the old "MegaRAID" Driver
.Xr mfi 4
which does not connect targets 
to the 
.Xr cam 4
layer and thus requires a new driver which attaches targets to the 
.Xr cam 4 
layer.
Older MegaRAID controllers are supported by
.Xr mfi 4
and will not work with
.Nm ,
but both the
.Xr mfi 4
and 
.Nm
drivers can detect and manage the LSI MegaRAID SAS 2208/2308/3008/3108 series of
controllers.
.Pp
The
.Xr device.hints 5
option is provided to tune the
.Nm
driver's behavior for LSI MegaRAID SAS 2208/2308/3008/3108 controllers.
By default, the
.Xr mfi 4
driver will detect these controllers.
See the 
.Nm PRIORITY 
section to know more about driver priority for MR-Fusion devices.
.Pp
.Nm
will provide a priority of (-30) (between
.Dv BUS_PROBE_DEFAULT
and
.Dv BUS_PROBE_LOW_PRIORITY )
at probe call for device id's 0x005B, 0x005D, and
0x005F so that
.Nm
does not take control of these devices without user intervention.
.Sh HARDWARE
The
.Nm
driver supports the following hardware:
.Pp
[ Thunderbolt 6Gb/s MR controller ]
.Bl -bullet -compact
.It
LSI MegaRAID SAS 9265
.It
LSI MegaRAID SAS 9266
.It
LSI MegaRAID SAS 9267
.It
LSI MegaRAID SAS 9270
.It
LSI MegaRAID SAS 9271
.It
LSI MegaRAID SAS 9272
.It
LSI MegaRAID SAS 9285
.It
LSI MegaRAID SAS 9286
.It
DELL PERC H810
.It
DELL PERC H710/P
.El
.Pp
[ Invader/Fury 12Gb/s MR controller ]
.Bl -bullet -compact
.It
LSI MegaRAID SAS 9380
.It
LSI MegaRAID SAS 9361
.It
LSI MegaRAID SAS 9341
.It
DELL PERC H830
.It
DELL PERC H730/P
.It
DELL PERC H330
.El
.Sh CONFIGURATION
To disable Online Controller Reset(OCR) for a specific
.Nm
driver instance, set the 
following tunable value in
.Xr loader.conf 5 :
.Bd -literal -offset indent
dev.mrsas.X.disable_ocr=1 
.Ed
.Pp
where X is the adapter number.
.Pp
To change the I/O timeout value for a specific 
.Nm
driver instance, set the following tunable value in
.Xr loader.conf 5 :
.Bd -literal -offset indent
dev.mrsas.X.mrsas_io_timeout=NNNNNN
.Ed
.Pp
where NNNNNN is the timeout value in milli-seconds.
.Pp
To change the firmware fault check timer value for a specific
.Nm
driver instance, set the following tunable value in
.Xr loader.conf 5 :
.Bd -literal -offset indent
dev.mrsas.X.mrsas_fw_fault_check_delay=NN
.Ed
.Pp
where NN is the fault check delay value in seconds.
.Pp
The current number of active I/O commands is shown in the
.Va dev.mrsas.X.fw_outstanding
.Xr sysctl 8
variable.
.Sh DEBUGGING
To enable debugging prints from the
.Nm
driver, set the
.Va hw.mrsas.X.debug_level
variable, where X is the adapter number, either in
.Xr loader.conf 5
or via
.Xr sysctl 8 .
The following bits have the described effects:
.Bl -tag -offset indent
.It 0x01
Enable informational prints.
.It 0x02
Enable tracing prints.
.It 0x04
Enable prints for driver faults.
.It 0x08
Enable prints for OCR and I/O timeout.
.It 0x10
Enable prints for AEN events.
.El
.Sh PRIORITY
The
.Nm
driver will always set a default (-30) priority in the PCI subsystem for
selection of MR-Fusion cards.
(It is between
.Dv BUS_PROBE_DEFAULT
and
.Dv BUS_PROBE_LOW_PRIORITY ) .
MR-Fusion Controllers include all cards with the
Device IDs -
0x005B, 
0x005D,
0x005F.
.Pp
The
.Xr mfi 4 
driver will set a priority of either
.Dv BUS_PROBE_DEFAULT
or
.Dv BUS_PROBE_LOW_PRIORITY
(depending on the device.hints setting) in the PCI
subsystem for selection of MR-Fusion cards.
With the above design in place, the
.Xr mfi 4
driver will attach to a MR-Fusion card given that it has a higher priority than
.Nm .
.Pp
Using
.Pa /boot/device.hints
(as mentioned below), the user can provide a preference
for the
.Nm
driver to detect a MR-Fusion card instead of the
.Xr mfi 4
driver. 
.Bd -ragged -offset indent
.Cd hw.mfi.mrsas_enable="1"
.Ed
.Pp
At boot time, the
.Xr mfi 4 
driver will get priority to detect MR-Fusion controllers by default.
Before
changing this default driver selection policy, LSI advises users to understand
how the driver selection policy works.
LSI's policy is to provide priority to
the
.Xr mfi 4
driver to detect MR-Fusion cards, but allow for the ability to choose the
.Nm
driver to detect MR-Fusion cards.
.Pp
LSI recommends setting hw.mfi.mrsas_enable="0" for customers who are using the
older 
.Xr mfi 4 
driver and do not want to switch to 
.Nm .
For those customers who are using a MR-Fusion controller for the first time, LSI
recommends using the
.Nm
driver and setting hw.mfi.mrsas_enable="1".
.Pp
Changing the default behavior is well tested under most conditions, but
unexpected behavior may pop up if more complex and unrealistic operations are
executed by switching between the
.Xr mfi 4
and 
.Nm 
drivers for MR-Fusion.
Switching drivers is designed to happen only one time.
Although multiple
switching is possible, it is not recommended.
The user should decide from
.Nm Start of Day
which driver they want to use for the MR-Fusion card.
.Pp
The user may see different device names when switching from 
.Xr mfi 4 
to 
.Nm .
This behavior is
.Nm Functions As Designed
and the user needs to change the
.Xr fstab 5
entry manually if they are doing any experiments with 
.Xr mfi 4 
and
.Nm
interoperability.
.Sh FILES
.Bl -tag -width ".Pa /dev/mrsas?" -compact
.It Pa /dev/da?
array/logical disk interface
.It Pa /dev/mrsas?
management interface
.El
.Sh SEE ALSO
.Xr cam 4 ,
.Xr mfi 4 ,
.Xr pci 4 ,
.Xr device.hints 5 ,
.Xt camcontrol 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 10.1 .
.Bd -ragged
.Cd "mfi Driver:"
.Xr mfi 4
is the old
.Fx
driver which started with support for Gen-1 Controllers and
was extended to support up to MR-Fusion (Device ID = 0x005B, 0x005D, 0x005F).
.Ed
.Bd -ragged
.Cd "mrsas Driver:"
.Nm
is the new driver reworked by LSI which supports Thunderbolt and onward
products.
The SAS+SATA RAID controller with device id 0x005b is referred to as
the Thunderbolt controller throughout this man page.
.Ed 
.Bd -ragged
.Nm cam aware HBA drivers:
.Fx
has a
.Xr cam 4
layer which attaches storage devices and provides a common access mechanism to
storage controllers and attached devices.
The
.Nm 
driver is
.Xr cam 4
aware and devices associated with 
.Nm 
can be seen using 
.Xr camcontrol 8 .
The
.Xr mfi 4
driver does not understand the
.Xr cam 4
layer and it directly associates storage disks to the block layer.
.Pp
.Nm Thunderbolt Controller: 
This is the 6Gb/s MegaRAID HBA card which has device id 0x005B.
.Pp
.Nm Invader Controller: 
This is 12Gb/s MegaRAID HBA card which has device id 0x005D.
.Pp
.Nm Fury Controller: 
This is the 12Gb/s MegaRAID HBA card which has device id 0x005F.
.Ed
.Sh AUTHORS
The
.Nm
driver and this manual page were written by
.An Kashyap Desai Aq Kashyap.Desai@lsi.com .
.Sh TODO
The driver does not support big-endian architectures at this time.
.Pp
The driver does not support alias for device name (it is required when the user
switches between two drivers and does not want to edit
.Pa /etc/fstab
manually).
.Pp
The
.Nm 
driver exposes devices as
.Pa /dev/da? ,
whereas 
.Xr mfi 4 
exposes devices as
.Pa /dev/mfid? .
.Pp
.Nm
does not support the Linux Emulator interface.
.Pp
.Nm
will not work with
.Xr mfiutil 8 .