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What is it? |
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----------- |
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It unhides the SMBus of Intel ICH southbridges hidden |
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on ASUS P4B series. It is implemented as a module (p4b_smbus.o), |
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or a shell script for the 2.6 kernel (unhide_ICH_SMBus). |
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It works with the following chips: |
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* ICH2 (82801BA) |
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* ICH2-M (82801BAM) |
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* ICH4 (82801DB) |
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* ICH4-M (82801DBM) |
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* ICH5 (82801EB) |
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ASUS switches off the SMBus PCI Device in the i801 ICH chip. I spoke twice |
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with the German support and learned that: "We do not want the users to be |
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irritated by just another PCI Device in the Win98 device manager." |
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Really funny :-). |
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This module is for 2.4 kernels only. For 2.6 kernels, activation is |
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handled by the code in drivers/pci/quirks.c in the kernel source. If you |
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have the 2.6 kernel and the quirks code does not activate your SMBus, |
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you may: |
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* check if you have kernel version from 2.6.17 to 2.6.19 |
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If so you, need to disable ACPI sleep support and recompile kernel. |
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If you don't use suspend try below instead of recompilation. |
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* run as root the ./unhide_ICH_SMBus script. It will unhide the bus |
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and load the i2c-i801 driver. Beware that you should then no longer |
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use system suspend as bad things might happen on resume. |
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* if above script works and you have latest kernel, you may |
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try to fix the quirks.c, recompile and test your new kernel, |
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and then submit a patch to us. Contact us if you need assistance. |
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Information for 2.4 users continues below. |
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NOTE: As of kernel 2.4.23, the kernel activates the SMBus PCI device |
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on the following boards: |
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* Asus P4B |
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* Asus P4B533 |
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* Asus P4PE |
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* Asus P4T533 |
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* Asus P4G8X Deluxe |
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So this module is no longer required for these boards. For the other |
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affected boards, it still is. |
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What does the module do? |
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------------------------ |
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(Note: the following instructions assume the ICH2. For the ICH4, |
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the PCI IDs are 24C0 and 24C3) |
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It turnes off (!) the bits number 8 and 3 in the LPC register of the ICH2. |
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This you can also try as root with setpci and pcitweak. |
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First do a: |
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setpci -d 8086:2440 f2.w |
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You will get an hex number VAL - in my case 148 (Hex)-, where you have to |
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erase the two bits - in my case you get 40 (Hex). |
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Then do a: |
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setpci -d 8086:2440 f2.w=VAL |
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Running "lspci -n" you will not see any new device, but with "pcitweak -l" you |
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should get a line similar to this in the output: |
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PCI: 00:1f:3: chip 8086,2443 card 1043,8028 rev 12 class 0c,05,00 hdr 00 |
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The important thing is the "8086,2443" here. |
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The device is activated, but not included in /proc/pci and |
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/proc/bus/pci/devices. This is the reason for running the module. |
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What are the system requirements? |
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--------------------------------- |
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- Obviously a board with Intel i801BA/DB/EB ICH2/4/5 with broken BIOS. |
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- A linux working with a 2.4 kernel AND hotplug support in it! |
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- A installed kernel tree and gcc. |
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- i2c and sensor modules installed. |
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How to install? |
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--------------- |
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Simply do a: |
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make -f Makefile.p4b |
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insmod p4b_smbus.o |
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modprobe i2c-core |
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modprobe i2c-i801 |
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modprobe i2c-dev |
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modprobe i2c-proc |
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Then run your sensor: |
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modprobe w83781d |
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What should i never do? |
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----------------------- |
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Do not try to do a "rmmod p4b_smbus" before a "rmmod i2c-i801". |
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The other way around should be okay. Otherwise you remove the PCI device |
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without notifying the i2c driver. |
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------------------------------- |
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| 108 |
Ilja Rauhut <IljaRauhut@web.de> |
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