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Based on kernel version 3.9. Page generated on 2013-05-02 23:08 EST.

1	Kernel driver i2c-i801
2	
3	Supported adapters:
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)
10	  * Intel 6300ESB
11	  * Intel 82801FB/FR/FW/FRW (ICH6)
12	  * Intel 82801G (ICH7)
13	  * Intel 631xESB/632xESB (ESB2)
14	  * Intel 82801H (ICH8)
15	  * Intel 82801I (ICH9)
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)
24	  * Intel Lynx Point-LP (PCH)
25	  * Intel Avoton (SOC)
26	  * Intel Wellsburg (PCH)
27	   Datasheets: Publicly available at the Intel website
28	
29	On Intel Patsburg and later chipsets, both the normal host SMBus controller
30	and the additional 'Integrated Device Function' controllers are supported.
31	
32	Authors: 
33		Mark Studebaker <mdsxyz123@yahoo.com>
34		Jean Delvare <khali@linux-fr.org>
35	
36	
37	Module Parameters
38	-----------------
39	
40	* disable_features (bit vector)
41	Disable selected features normally supported by the device. This makes it
42	possible to work around possible driver or hardware bugs if the feature in
43	question doesn't work as intended for whatever reason. Bit values:
44	 0x01  disable SMBus PEC
45	 0x02  disable the block buffer
46	 0x08  disable the I2C block read functionality
47	 0x10  don't use interrupts
48	
49	
50	Description
51	-----------
52	
53	The ICH (properly known as the 82801AA), ICH0 (82801AB), ICH2 (82801BA),
54	ICH3 (82801CA/CAM) and later devices (PCH) are Intel chips that are a part of
55	Intel's '810' chipset for Celeron-based PCs, '810E' chipset for
56	Pentium-based PCs, '815E' chipset, and others.
57	
58	The ICH chips contain at least SEVEN separate PCI functions in TWO logical
59	PCI devices. An output of lspci will show something similar to the
60	following:
61	
62	  00:1e.0 PCI bridge: Intel Corporation: Unknown device 2418 (rev 01)
63	  00:1f.0 ISA bridge: Intel Corporation: Unknown device 2410 (rev 01)
64	  00:1f.1 IDE interface: Intel Corporation: Unknown device 2411 (rev 01)
65	  00:1f.2 USB Controller: Intel Corporation: Unknown device 2412 (rev 01)
66	  00:1f.3 Unknown class [0c05]: Intel Corporation: Unknown device 2413 (rev 01)
67	
68	The SMBus controller is function 3 in device 1f. Class 0c05 is SMBus Serial
69	Controller.
70	
71	The ICH chips are quite similar to Intel's PIIX4 chip, at least in the
72	SMBus controller.
73	
74	
75	Process Call Support
76	--------------------
77	
78	Not supported.
79	
80	
81	I2C Block Read Support
82	----------------------
83	
84	I2C block read is supported on the 82801EB (ICH5) and later chips.
85	
86	
87	SMBus 2.0 Support
88	-----------------
89	
90	The 82801DB (ICH4) and later chips support several SMBus 2.0 features.
91	
92	
93	Interrupt Support
94	-----------------
95	
96	PCI interrupt support is supported on the 82801EB (ICH5) and later chips.
97	
98	
99	Hidden ICH SMBus
100	----------------
101	
102	If your system has an Intel ICH south bridge, but you do NOT see the
103	SMBus device at 00:1f.3 in lspci, and you can't figure out any way in the
104	BIOS to enable it, it means it has been hidden by the BIOS code. Asus is
105	well known for first doing this on their P4B motherboard, and many other
106	boards after that. Some vendor machines are affected as well.
107	
108	The first thing to try is the "i2c_ec" ACPI driver. It could be that the
109	SMBus was hidden on purpose because it'll be driven by ACPI. If the
110	i2c_ec driver works for you, just forget about the i2c-i801 driver and
111	don't try to unhide the ICH SMBus. Even if i2c_ec doesn't work, you
112	better make sure that the SMBus isn't used by the ACPI code. Try loading
113	the "fan" and "thermal" drivers, and check in /proc/acpi/fan and
114	/proc/acpi/thermal_zone. If you find anything there, it's likely that
115	the ACPI is accessing the SMBus and it's safer not to unhide it. Only
116	once you are certain that ACPI isn't using the SMBus, you can attempt
117	to unhide it.
118	
119	In order to unhide the SMBus, we need to change the value of a PCI
120	register before the kernel enumerates the PCI devices. This is done in
121	drivers/pci/quirks.c, where all affected boards must be listed (see
122	function asus_hides_smbus_hostbridge.) If the SMBus device is missing,
123	and you think there's something interesting on the SMBus (e.g. a
124	hardware monitoring chip), you need to add your board to the list.
125	
126	The motherboard is identified using the subvendor and subdevice IDs of the
127	host bridge PCI device. Get yours with "lspci -n -v -s 00:00.0":
128	
129	00:00.0 Class 0600: 8086:2570 (rev 02)
130	        Subsystem: 1043:80f2
131	        Flags: bus master, fast devsel, latency 0
132	        Memory at fc000000 (32-bit, prefetchable) [size=32M]
133	        Capabilities: [e4] #09 [2106]
134	        Capabilities: [a0] AGP version 3.0
135	
136	Here the host bridge ID is 2570 (82865G/PE/P), the subvendor ID is 1043
137	(Asus) and the subdevice ID is 80f2 (P4P800-X). You can find the symbolic
138	names for the bridge ID and the subvendor ID in include/linux/pci_ids.h,
139	and then add a case for your subdevice ID at the right place in
140	drivers/pci/quirks.c. Then please give it very good testing, to make sure
141	that the unhidden SMBus doesn't conflict with e.g. ACPI.
142	
143	If it works, proves useful (i.e. there are usable chips on the SMBus)
144	and seems safe, please submit a patch for inclusion into the kernel.
145	
146	Note: There's a useful script in lm_sensors 2.10.2 and later, named
147	unhide_ICH_SMBus (in prog/hotplug), which uses the fakephp driver to
148	temporarily unhide the SMBus without having to patch and recompile your
149	kernel. It's very convenient if you just want to check if there's
150	anything interesting on your hidden ICH SMBus.
151	
152	
153	**********************
154	The lm_sensors project gratefully acknowledges the support of Texas
155	Instruments in the initial development of this driver.
156	
157	The lm_sensors project gratefully acknowledges the support of Intel in the
158	development of SMBus 2.0 / ICH4 features of this driver.
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