| 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, 32 byte buffer not supported) |
| * Intel 82801EB/ER (ICH5) (HW PEC supported, 32 byte buffer not supported) |
| * Intel 6300ESB |
| * Intel 82801FB/FR/FW/FRW (ICH6) |
| * Intel 82801G (ICH7) |
| * Intel 631xESB/632xESB (ESB2) |
| * Intel 82801H (ICH8) |
| * Intel ICH9 |
| Datasheets: Publicly available at the Intel website |
| |
| Authors: |
| Frodo Looijaard <frodol@dds.nl>, |
| Philip Edelbrock <phil@netroedge.com>, |
| Mark Studebaker <mdsxyz123@yahoo.com> |
| |
| |
| Module Parameters |
| ----------------- |
| |
| None. |
| |
| |
| Description |
| ----------- |
| |
| The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA), |
| ICH3 (82801CA/CAM) and later devices 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 |
| following: |
| |
| 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 |
| Controller. |
| |
| 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 |
| ---------------------- |
| |
| Not supported at the moment. |
| |
| |
| SMBus 2.0 Support |
| ----------------- |
| |
| The 82801DB (ICH4) and later chips support several SMBus 2.0 features. |
| |
| |
| 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. |