diff options
author | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 12:17:53 -0700 |
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committer | Yunhong Jiang <yunhong.jiang@intel.com> | 2015-08-04 15:44:42 -0700 |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/i2c/busses/i2c-piix4 | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/Documentation/i2c/busses/i2c-piix4')
-rw-r--r-- | kernel/Documentation/i2c/busses/i2c-piix4 | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/kernel/Documentation/i2c/busses/i2c-piix4 b/kernel/Documentation/i2c/busses/i2c-piix4 new file mode 100644 index 000000000..aa959fd22 --- /dev/null +++ b/kernel/Documentation/i2c/busses/i2c-piix4 @@ -0,0 +1,110 @@ +Kernel driver i2c-piix4 + +Supported adapters: + * Intel 82371AB PIIX4 and PIIX4E + * Intel 82443MX (440MX) + Datasheet: Publicly available at the Intel website + * ServerWorks OSB4, CSB5, CSB6, HT-1000 and HT-1100 southbridges + Datasheet: Only available via NDA from ServerWorks + * ATI IXP200, IXP300, IXP400, SB600, SB700 and SB800 southbridges + Datasheet: Not publicly available + SB700 register reference available at: + http://support.amd.com/us/Embedded_TechDocs/43009_sb7xx_rrg_pub_1.00.pdf + * AMD SP5100 (SB700 derivative found on some server mainboards) + Datasheet: Publicly available at the AMD website + http://support.amd.com/us/Embedded_TechDocs/44413.pdf + * AMD Hudson-2, ML, CZ + Datasheet: Not publicly available + * Standard Microsystems (SMSC) SLC90E66 (Victory66) southbridge + Datasheet: Publicly available at the SMSC website http://www.smsc.com + +Authors: + Frodo Looijaard <frodol@dds.nl> + Philip Edelbrock <phil@netroedge.com> + + +Module Parameters +----------------- + +* force: int + Forcibly enable the PIIX4. DANGEROUS! +* force_addr: int + Forcibly enable the PIIX4 at the given address. EXTREMELY DANGEROUS! + + +Description +----------- + +The PIIX4 (properly known as the 82371AB) is an Intel chip with a lot of +functionality. Among other things, it implements the PCI bus. One of its +minor functions is implementing a System Management Bus. This is a true +SMBus - you can not access it on I2C levels. The good news is that it +natively understands SMBus commands and you do not have to worry about +timing problems. The bad news is that non-SMBus devices connected to it can +confuse it mightily. Yes, this is known to happen... + +Do 'lspci -v' and see whether it contains an entry like this: + +0000:00:02.3 Bridge: Intel Corp. 82371AB/EB/MB PIIX4 ACPI (rev 02) + Flags: medium devsel, IRQ 9 + +Bus and device numbers may differ, but the function number must be +identical (like many PCI devices, the PIIX4 incorporates a number of +different 'functions', which can be considered as separate devices). If you +find such an entry, you have a PIIX4 SMBus controller. + +On some computers (most notably, some Dells), the SMBus is disabled by +default. If you use the insmod parameter 'force=1', the kernel module will +try to enable it. THIS IS VERY DANGEROUS! If the BIOS did not set up a +correct address for this module, you could get in big trouble (read: +crashes, data corruption, etc.). Try this only as a last resort (try BIOS +updates first, for example), and backup first! An even more dangerous +option is 'force_addr=<IOPORT>'. This will not only enable the PIIX4 like +'force' foes, but it will also set a new base I/O port address. The SMBus +parts of the PIIX4 needs a range of 8 of these addresses to function +correctly. If these addresses are already reserved by some other device, +you will get into big trouble! DON'T USE THIS IF YOU ARE NOT VERY SURE +ABOUT WHAT YOU ARE DOING! + +The PIIX4E is just an new version of the PIIX4; it is supported as well. +The PIIX/PIIX3 does not implement an SMBus or I2C bus, so you can't use +this driver on those mainboards. + +The ServerWorks Southbridges, the Intel 440MX, and the Victory66 are +identical to the PIIX4 in I2C/SMBus support. + +The AMD SB700, SB800, SP5100 and Hudson-2 chipsets implement two +PIIX4-compatible SMBus controllers. If your BIOS initializes the +secondary controller, it will be detected by this driver as +an "Auxiliary SMBus Host Controller". + +If you own Force CPCI735 motherboard or other OSB4 based systems you may need +to change the SMBus Interrupt Select register so the SMBus controller uses +the SMI mode. + +1) Use lspci command and locate the PCI device with the SMBus controller: + 00:0f.0 ISA bridge: ServerWorks OSB4 South Bridge (rev 4f) + The line may vary for different chipsets. Please consult the driver source + for all possible PCI ids (and lspci -n to match them). Lets assume the + device is located at 00:0f.0. +2) Now you just need to change the value in 0xD2 register. Get it first with + command: lspci -xxx -s 00:0f.0 + If the value is 0x3 then you need to change it to 0x1 + setpci -s 00:0f.0 d2.b=1 + +Please note that you don't need to do that in all cases, just when the SMBus is +not working properly. + + +Hardware-specific issues +------------------------ + +This driver will refuse to load on IBM systems with an Intel PIIX4 SMBus. +Some of these machines have an RFID EEPROM (24RF08) connected to the SMBus, +which can easily get corrupted due to a state machine bug. These are mostly +Thinkpad laptops, but desktop systems may also be affected. We have no list +of all affected systems, so the only safe solution was to prevent access to +the SMBus on all IBM systems (detected using DMI data.) + +For additional information, read: +http://www.lm-sensors.org/browser/lm-sensors/trunk/README |