Commit d1bdc40b authored by Corey Minyard's avatar Corey Minyard Committed by Linus Torvalds
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IPMI: Remove SMBus driver info from the docs

Some documentation for the SMBus driver is in the IPMI docs, but that
code is not in the kernel tree at this point.  So remove the docs to
avoid confusion.
Signed-off-by: default avatarCorey Minyard <>
Signed-off-by: default avatarLinus Torvalds <>
parent ddffeb8c
......@@ -42,13 +42,7 @@ The driver interface depends on your hardware. If your system
properly provides the SMBIOS info for IPMI, the driver will detect it
and just work. If you have a board with a standard interface (These
will generally be either "KCS", "SMIC", or "BT", consult your hardware
manual), choose the 'IPMI SI handler' option. A driver also exists
for direct I2C access to the IPMI management controller. Some boards
support this, but it is unknown if it will work on every board. For
this, choose 'IPMI SMBus handler', but be ready to try to do some
figuring to see if it will work on your system if the SMBIOS/APCI
information is wrong or not present. It is fairly safe to have both
these enabled and let the drivers auto-detect what is present.
manual), choose the 'IPMI SI handler' option.
You should generally enable ACPI on your system, as systems with IPMI
can have ACPI tables describing them.
......@@ -58,8 +52,7 @@ their job correctly, the IPMI controller should be automatically
detected (via ACPI or SMBIOS tables) and should just work. Sadly,
many boards do not have this information. The driver attempts
standard defaults, but they may not work. If you fall into this
situation, you need to read the section below named 'The SI Driver' or
"The SMBus Driver" on how to hand-configure your system.
situation, you need to read the section below named 'The SI Driver'.
IPMI defines a standard watchdog timer. You can enable this with the
'IPMI Watchdog Timer' config option. If you compile the driver into
......@@ -104,12 +97,7 @@ driver, each open file for this device ties in to the message handler
as an IPMI user.
ipmi_si - A driver for various system interfaces. This supports KCS,
SMIC, and BT interfaces. Unless you have an SMBus interface or your
own custom interface, you probably need to use this.
ipmi_smb - A driver for accessing BMCs on the SMBus. It uses the
I2C kernel driver's SMBus interfaces to send and receive IPMI messages
over the SMBus.
SMIC, and BT interfaces.
ipmi_watchdog - IPMI requires systems to have a very capable watchdog
timer. This driver implements the standard Linux watchdog timer
......@@ -482,53 +470,6 @@ for specifying an interface. Note that when removing an interface,
only the first three parameters (si type, address type, and address)
are used for the comparison. Any options are ignored for removing.
The SMBus Driver
The SMBus driver allows up to 4 SMBus devices to be configured in the
system. By default, the driver will register any SMBus interfaces it finds
in the I2C address range of 0x20 to 0x4f on any adapter. You can change this
at module load time (for a module) with:
modprobe ipmi_smb.o
[defaultprobe=1] [dbg_probe=1]
The addresses are specified in pairs, the first is the adapter ID and the
second is the I2C address on that adapter.
The debug flags are bit flags for each BMC found, they are:
IPMI messages: 1, driver state: 2, timing: 4, I2C probe: 8
Setting smb_defaultprobe to zero disabled the default probing of SMBus
interfaces at address range 0x20 to 0x4f. This means that only the
BMCs specified on the smb_addr line will be detected.
Setting smb_dbg_probe to 1 will enable debugging of the probing and
detection process for BMCs on the SMBusses.
Discovering the IPMI compliant BMC on the SMBus can cause devices
on the I2C bus to fail. The SMBus driver writes a "Get Device ID" IPMI
message as a block write to the I2C bus and waits for a response.
This action can be detrimental to some I2C devices. It is highly recommended
that the known I2c address be given to the SMBus driver in the smb_addr
parameter. The default address range will not be used when a smb_addr
parameter is provided.
When compiled into the kernel, the addresses can be specified on the
kernel command line as:
ipmi_smb.defaultprobe=0 ipmi_smb.dbg_probe=1
These are the same options as on the module command line.
Note that you might need some I2C changes if CONFIG_IPMI_PANIC_EVENT
is enabled along with this, so the I2C driver knows to run to
completion during sending a panic event.
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