7 * Intel 82801AA and 82801AB (ICH and ICH0 - part of the
8 '810' and '810E' chipsets)
9 * Intel 82801BA (ICH2 - part of the '815E' chipset)
10 * Intel 82801CA/CAM (ICH3)
11 * Intel 82801DB (ICH4) (HW PEC supported)
12 * Intel 82801EB/ER (ICH5) (HW PEC supported)
14 * Intel 82801FB/FR/FW/FRW (ICH6)
16 * Intel 631xESB/632xESB (ESB2)
19 * Intel EP80579 (Tolapai)
20 * Intel 82801JI (ICH10)
21 * Intel 5/3400 Series (PCH)
22 * Intel 6 Series (PCH)
23 * Intel Patsburg (PCH)
24 * Intel DH89xxCC (PCH)
25 * Intel Panther Point (PCH)
26 * Intel Lynx Point (PCH)
28 * Intel Wellsburg (PCH)
29 * Intel Coleto Creek (PCH)
30 * Intel Wildcat Point (PCH)
31 * Intel BayTrail (SOC)
32 * Intel Braswell (SOC)
33 * Intel Sunrise Point (PCH)
34 * Intel Kaby Lake (PCH)
37 * Intel Lewisburg (PCH)
38 * Intel Gemini Lake (SOC)
39 * Intel Cannon Lake (PCH)
40 * Intel Cedar Fork (PCH)
41 * Intel Ice Lake (PCH)
42 * Intel Comet Lake (PCH)
43 * Intel Elkhart Lake (PCH)
44 * Intel Tiger Lake (PCH)
45 * Intel Jasper Lake (SOC)
46 * Intel Emmitsburg (PCH)
47 * Intel Alder Lake (PCH)
48 * Intel Raptor Lake (PCH)
50 Datasheets: Publicly available at the Intel website
52 On Intel Patsburg and later chipsets, both the normal host SMBus controller
53 and the additional 'Integrated Device Function' controllers are supported.
56 - Mark Studebaker <mdsxyz123@yahoo.com>
57 - Jean Delvare <jdelvare@suse.de>
63 * disable_features (bit vector)
65 Disable selected features normally supported by the device. This makes it
66 possible to work around possible driver or hardware bugs if the feature in
67 question doesn't work as intended for whatever reason. Bit values:
69 ==== =========================================
70 0x01 disable SMBus PEC
71 0x02 disable the block buffer
72 0x08 disable the I2C block read functionality
73 0x10 don't use interrupts
74 0x20 disable SMBus Host Notify
75 ==== =========================================
81 The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
82 ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
83 Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
84 Pentium-based PCs, '815E' chipset, and others.
86 The ICH chips contain at least SEVEN separate PCI functions in TWO logical
87 PCI devices. An output of lspci will show something similar to the
90 00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
91 00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
92 00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
93 00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
94 00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
96 The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
99 The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
106 Block process call is supported on the 82801EB (ICH5) and later chips.
109 I2C Block Read Support
110 ----------------------
112 I2C block read is supported on the 82801EB (ICH5) and later chips.
118 The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
124 PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
130 If your system has an Intel ICH south bridge, but you do NOT see the
131 SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
132 BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
133 well known for first doing this on their P4B motherboard, and many other
134 boards after that. Some vendor machines are affected as well.
136 The first thing to try is the "i2c-scmi" ACPI driver. It could be that the
137 SMBus was hidden on purpose because it'll be driven by ACPI. If the
138 i2c-scmi driver works for you, just forget about the i2c-i801 driver and
139 don't try to unhide the ICH SMBus. Even if i2c-scmi doesn't work, you
140 better make sure that the SMBus isn't used by the ACPI code. Try loading
141 the "fan" and "thermal" drivers, and check in /sys/class/thermal. If you
142 find a thermal zone with type "acpitz", it's likely that the ACPI is
143 accessing the SMBus and it's safer not to unhide it. Only once you are
144 certain that ACPI isn't using the SMBus, you can attempt to unhide it.
146 In order to unhide the SMBus, we need to change the value of a PCI
147 register before the kernel enumerates the PCI devices. This is done in
148 drivers/pci/quirks.c, where all affected boards must be listed (see
149 function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
150 and you think there's something interesting on the SMBus (e.g. a
151 hardware monitoring chip), you need to add your board to the list.
153 The motherboard is identified using the subvendor and subdevice IDs of the
154 host bridge PCI device. Get yours with ``lspci -n -v -s 00:00.0``::
156 00:00.0 Class 0600: 8086:2570 (rev 02)
158 Flags: bus master, fast devsel, latency 0
159 Memory at fc000000 (32-bit, prefetchable) [size=32M]
160 Capabilities: [e4] #09 [2106]
161 Capabilities: [a0] AGP version 3.0
163 Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
164 (Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
165 names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
166 and then add a case for your subdevice ID at the right place in
167 drivers/pci/quirks.c. Then please give it very good testing, to make sure
168 that the unhidden SMBus doesn't conflict with e.g. ACPI.
170 If it works, proves useful (i.e. there are usable chips on the SMBus)
171 and seems safe, please submit a patch for inclusion into the kernel.
173 Note: There's a useful script in lm_sensors 2.10.2 and later, named
174 unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
175 temporarily unhide the SMBus without having to patch and recompile your
176 kernel. It's very convenient if you just want to check if there's
177 anything interesting on your hidden ICH SMBus.
180 ----------------------------------------------------------------------------
182 The lm_sensors project gratefully acknowledges the support of Texas
183 Instruments in the initial development of this driver.
185 The lm_sensors project gratefully acknowledges the support of Intel in the
186 development of SMBus 2.0 / ICH4 features of this driver.