4 * Intel 82801AA and 82801AB (ICH and ICH0 - part of the
5 '810' and '810E' chipsets)
6 * Intel 82801BA (ICH2 - part of the '815E' chipset)
7 * Intel 82801CA/CAM (ICH3)
8 * Intel 82801DB (ICH4) (HW PEC supported)
9 * Intel 82801EB/ER (ICH5) (HW PEC supported)
11 * Intel 82801FB/FR/FW/FRW (ICH6)
13 * Intel 631xESB/632xESB (ESB2)
16 * Intel EP80579 (Tolapai)
17 * Intel 82801JI (ICH10)
18 * Intel 5/3400 Series (PCH)
19 * Intel 6 Series (PCH)
20 * Intel Patsburg (PCH)
21 * Intel DH89xxCC (PCH)
22 * Intel Panther Point (PCH)
23 * Intel Lynx Point (PCH)
25 * Intel Wellsburg (PCH)
26 * Intel Coleto Creek (PCH)
27 * Intel Wildcat Point (PCH)
28 * Intel BayTrail (SOC)
29 * Intel Braswell (SOC)
30 * Intel Sunrise Point (PCH)
31 * Intel Kaby Lake (PCH)
34 * Intel Lewisburg (PCH)
35 * Intel Gemini Lake (SOC)
36 * Intel Cannon Lake (PCH)
37 * Intel Cedar Fork (PCH)
38 * Intel Ice Lake (PCH)
39 * Intel Comet Lake (PCH)
40 * Intel Elkhart Lake (PCH)
41 * Intel Tiger Lake (PCH)
42 Datasheets: Publicly available at the Intel website
44 On Intel Patsburg and later chipsets, both the normal host SMBus controller
45 and the additional 'Integrated Device Function' controllers are supported.
48 Mark Studebaker <mdsxyz123@yahoo.com>
49 Jean Delvare <jdelvare@suse.de>
55 * disable_features (bit vector)
56 Disable selected features normally supported by the device. This makes it
57 possible to work around possible driver or hardware bugs if the feature in
58 question doesn't work as intended for whatever reason. Bit values:
59 0x01 disable SMBus PEC
60 0x02 disable the block buffer
61 0x08 disable the I2C block read functionality
62 0x10 don't use interrupts
63 0x20 disable SMBus Host Notify
69 The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
70 ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
71 Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
72 Pentium-based PCs, '815E' chipset, and others.
74 The ICH chips contain at least SEVEN separate PCI functions in TWO logical
75 PCI devices. An output of lspci will show something similar to the
78 00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
79 00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
80 00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
81 00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
82 00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
84 The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
87 The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
94 Block process call is supported on the 82801EB (ICH5) and later chips.
97 I2C Block Read Support
98 ----------------------
100 I2C block read is supported on the 82801EB (ICH5) and later chips.
106 The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
112 PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
118 If your system has an Intel ICH south bridge, but you do NOT see the
119 SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
120 BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
121 well known for first doing this on their P4B motherboard, and many other
122 boards after that. Some vendor machines are affected as well.
124 The first thing to try is the "i2c-scmi" ACPI driver. It could be that the
125 SMBus was hidden on purpose because it'll be driven by ACPI. If the
126 i2c-scmi driver works for you, just forget about the i2c-i801 driver and
127 don't try to unhide the ICH SMBus. Even if i2c-scmi doesn't work, you
128 better make sure that the SMBus isn't used by the ACPI code. Try loading
129 the "fan" and "thermal" drivers, and check in /sys/class/thermal. If you
130 find a thermal zone with type "acpitz", it's likely that the ACPI is
131 accessing the SMBus and it's safer not to unhide it. Only once you are
132 certain that ACPI isn't using the SMBus, you can attempt to unhide it.
134 In order to unhide the SMBus, we need to change the value of a PCI
135 register before the kernel enumerates the PCI devices. This is done in
136 drivers/pci/quirks.c, where all affected boards must be listed (see
137 function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
138 and you think there's something interesting on the SMBus (e.g. a
139 hardware monitoring chip), you need to add your board to the list.
141 The motherboard is identified using the subvendor and subdevice IDs of the
142 host bridge PCI device. Get yours with "lspci -n -v -s 00:00.0":
144 00:00.0 Class 0600: 8086:2570 (rev 02)
146 Flags: bus master, fast devsel, latency 0
147 Memory at fc000000 (32-bit, prefetchable) [size=32M]
148 Capabilities: [e4] #09 [2106]
149 Capabilities: [a0] AGP version 3.0
151 Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
152 (Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
153 names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
154 and then add a case for your subdevice ID at the right place in
155 drivers/pci/quirks.c. Then please give it very good testing, to make sure
156 that the unhidden SMBus doesn't conflict with e.g. ACPI.
158 If it works, proves useful (i.e. there are usable chips on the SMBus)
159 and seems safe, please submit a patch for inclusion into the kernel.
161 Note: There's a useful script in lm_sensors 2.10.2 and later, named
162 unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
163 temporarily unhide the SMBus without having to patch and recompile your
164 kernel. It's very convenient if you just want to check if there's
165 anything interesting on your hidden ICH SMBus.
168 **********************
169 The lm_sensors project gratefully acknowledges the support of Texas
170 Instruments in the initial development of this driver.
172 The lm_sensors project gratefully acknowledges the support of Intel in the
173 development of SMBus 2.0 / ICH4 features of this driver.