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+Kernel driver i2c-i801
+Supported adapters:
+ * Intel 82801AA and 82801AB (ICH and ICH0 - part of the
+ '810' and '810E' chipsets)
+ * Intel 82801BA (ICH2 - part of the '815E' chipset)
+ * Intel 82801CA/CAM (ICH3)
+ * Intel 82801DB (ICH4) (HW PEC supported)
+ * Intel 82801EB/ER (ICH5) (HW PEC supported)
+ * Intel 6300ESB
+ * Intel 82801FB/FR/FW/FRW (ICH6)
+ * Intel 82801G (ICH7)
+ * Intel 631xESB/632xESB (ESB2)
+ * Intel 82801H (ICH8)
+ * Intel 82801I (ICH9)
+ * Intel EP80579 (Tolapai)
+ * Intel 82801JI (ICH10)
+ * Intel 5/3400 Series (PCH)
+ * Intel 6 Series (PCH)
+ * Intel Patsburg (PCH)
+ * Intel DH89xxCC (PCH)
+ * Intel Panther Point (PCH)
+ * Intel Lynx Point (PCH)
+ * Intel Lynx Point-LP (PCH)
+ * Intel Avoton (SOC)
+ * Intel Wellsburg (PCH)
+ Datasheets: Publicly available at the Intel website
+On Intel Patsburg and later chipsets, both the normal host SMBus controller
+and the additional 'Integrated Device Function' controllers are supported.
+ Mark Studebaker <mdsxyz123@yahoo.com>
+ Jean Delvare <khali@linux-fr.org>
+Module Parameters
+* disable_features (bit vector)
+Disable selected features normally supported by the device. This makes it
+possible to work around possible driver or hardware bugs if the feature in
+question doesn't work as intended for whatever reason. Bit values:
+ 0x01 disable SMBus PEC
+ 0x02 disable the block buffer
+ 0x08 disable the I2C block read functionality
+ 0x10 don't use interrupts
+The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
+ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
+Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
+Pentium-based PCs, '815E' chipset, and others.
+The ICH chips contain at least SEVEN separate PCI functions in TWO logical
+PCI devices. An output of lspci will show something similar to the
+ 00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
+ 00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
+ 00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
+ 00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
+ 00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
+The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
+The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
+SMBus controller.
+Process Call Support
+Not supported.
+I2C Block Read Support
+I2C block read is supported on the 82801EB (ICH5) and later chips.
+SMBus 2.0 Support
+The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
+Interrupt Support
+PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
+Hidden ICH SMBus
+If your system has an Intel ICH south bridge, but you do NOT see the
+SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
+BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
+well known for first doing this on their P4B motherboard, and many other
+boards after that. Some vendor machines are affected as well.
+The first thing to try is the "i2c_ec" ACPI driver. It could be that the
+SMBus was hidden on purpose because it'll be driven by ACPI. If the
+i2c_ec driver works for you, just forget about the i2c-i801 driver and
+don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you
+better make sure that the SMBus isn't used by the ACPI code. Try loading
+the "fan" and "thermal" drivers, and check in /proc/acpi/fan and
+/proc/acpi/thermal_zone. If you find anything there, it's likely that
+the ACPI is accessing the SMBus and it's safer not to unhide it. Only
+once you are certain that ACPI isn't using the SMBus, you can attempt
+to unhide it.
+In order to unhide the SMBus, we need to change the value of a PCI
+register before the kernel enumerates the PCI devices. This is done in
+drivers/pci/quirks.c, where all affected boards must be listed (see
+function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
+and you think there's something interesting on the SMBus (e.g. a
+hardware monitoring chip), you need to add your board to the list.
+The motherboard is identified using the subvendor and subdevice IDs of the
+host bridge PCI device. Get yours with "lspci -n -v -s 00:00.0":
+00:00.0 Class 0600: 8086:2570 (rev 02)
+ Subsystem: 1043:80f2
+ Flags: bus master, fast devsel, latency 0
+ Memory at fc000000 (32-bit, prefetchable) [size=32M]
+ Capabilities: [e4] #09 [2106]
+ Capabilities: [a0] AGP version 3.0
+Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
+(Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
+names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
+and then add a case for your subdevice ID at the right place in
+drivers/pci/quirks.c. Then please give it very good testing, to make sure
+that the unhidden SMBus doesn't conflict with e.g. ACPI.
+If it works, proves useful (i.e. there are usable chips on the SMBus)
+and seems safe, please submit a patch for inclusion into the kernel.
+Note: There's a useful script in lm_sensors 2.10.2 and later, named
+unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
+temporarily unhide the SMBus without having to patch and recompile your
+kernel. It's very convenient if you just want to check if there's
+anything interesting on your hidden ICH SMBus.
+The lm_sensors project gratefully acknowledges the support of Texas
+Instruments in the initial development of this driver.
+The lm_sensors project gratefully acknowledges the support of Intel in the
+development of SMBus 2.0 / ICH4 features of this driver.