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)
49 * Intel Meteor Lake (SOC and PCH)
50 * Intel Birch Stream (SOC)
52 Datasheets: Publicly available at the Intel website
54 On Intel Patsburg and later chipsets, both the normal host SMBus controller
55 and the additional 'Integrated Device Function' controllers are supported.
58 - Mark Studebaker <mdsxyz123@yahoo.com>
59 - Jean Delvare <jdelvare@suse.de>
65 * disable_features (bit vector)
67 Disable selected features normally supported by the device. This makes it
68 possible to work around possible driver or hardware bugs if the feature in
69 question doesn't work as intended for whatever reason. Bit values:
71 ==== =========================================
72 0x01 disable SMBus PEC
73 0x02 disable the block buffer
74 0x08 disable the I2C block read functionality
75 0x10 don't use interrupts
76 0x20 disable SMBus Host Notify
77 ==== =========================================
83 The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
84 ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
85 Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
86 Pentium-based PCs, '815E' chipset, and others.
88 The ICH chips contain at least SEVEN separate PCI functions in TWO logical
89 PCI devices. An output of lspci will show something similar to the
92 00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
93 00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
94 00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
95 00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
96 00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
98 The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
101 The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
108 Block process call is supported on the 82801EB (ICH5) and later chips.
111 I2C Block Read Support
112 ----------------------
114 I2C block read is supported on the 82801EB (ICH5) and later chips.
120 The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
126 PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
132 If your system has an Intel ICH south bridge, but you do NOT see the
133 SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
134 BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
135 well known for first doing this on their P4B motherboard, and many other
136 boards after that. Some vendor machines are affected as well.
138 The first thing to try is the "i2c-scmi" ACPI driver. It could be that the
139 SMBus was hidden on purpose because it'll be driven by ACPI. If the
140 i2c-scmi driver works for you, just forget about the i2c-i801 driver and
141 don't try to unhide the ICH SMBus. Even if i2c-scmi doesn't work, you
142 better make sure that the SMBus isn't used by the ACPI code. Try loading
143 the "fan" and "thermal" drivers, and check in /sys/class/thermal. If you
144 find a thermal zone with type "acpitz", it's likely that the ACPI is
145 accessing the SMBus and it's safer not to unhide it. Only once you are
146 certain that ACPI isn't using the SMBus, you can attempt to unhide it.
148 In order to unhide the SMBus, we need to change the value of a PCI
149 register before the kernel enumerates the PCI devices. This is done in
150 drivers/pci/quirks.c, where all affected boards must be listed (see
151 function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
152 and you think there's something interesting on the SMBus (e.g. a
153 hardware monitoring chip), you need to add your board to the list.
155 The motherboard is identified using the subvendor and subdevice IDs of the
156 host bridge PCI device. Get yours with ``lspci -n -v -s 00:00.0``::
158 00:00.0 Class 0600: 8086:2570 (rev 02)
160 Flags: bus master, fast devsel, latency 0
161 Memory at fc000000 (32-bit, prefetchable) [size=32M]
162 Capabilities: [e4] #09 [2106]
163 Capabilities: [a0] AGP version 3.0
165 Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
166 (Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
167 names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
168 and then add a case for your subdevice ID at the right place in
169 drivers/pci/quirks.c. Then please give it very good testing, to make sure
170 that the unhidden SMBus doesn't conflict with e.g. ACPI.
172 If it works, proves useful (i.e. there are usable chips on the SMBus)
173 and seems safe, please submit a patch for inclusion into the kernel.
175 Note: There's a useful script in lm_sensors 2.10.2 and later, named
176 unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
177 temporarily unhide the SMBus without having to patch and recompile your
178 kernel. It's very convenient if you just want to check if there's
179 anything interesting on your hidden ICH SMBus.
182 ----------------------------------------------------------------------------
184 The lm_sensors project gratefully acknowledges the support of Texas
185 Instruments in the initial development of this driver.
187 The lm_sensors project gratefully acknowledges the support of Intel in the
188 development of SMBus 2.0 / ICH4 features of this driver.