[ltp] lm sensors

[linux-thinkpad@www.bm-soft.com]

The 24Cxx devices are common.  We wrote a driver for them (eeprom.c).  
We are reasonably confident that they are safe, but it could be
possible that some makers aren't consistent with how they implement 
the client I2C protocol on the devices.

On Thinkpads (and most computers for that matter), there are a number
of I2C busses and devices in use.  Thinkpads have at least 2 busses,
but probably more than that (like for video and other subsystems).

Here are pictures and instructions for locating the 24RF08 on the 
Thinkpad 600e motherboard (thanks to Joe!):

http://www.ja.olm.net/unlock/key_for_600e.htm

There is also a link on that page to the hardware maintenance manual
which talks about the unit serial number, as well as a recovery
process (has anyone tried it?).  See page 20 (Acrobat reader calls it
page 26).  I also heard of hitting 'ESC' at the error message to fix 
it and continue the boot process... that sounds too easy, though.

Since you've got your board handy, could you see if you can find the
24RF08 on your board?  Or, tell us what chip is in it's place?  I
think there was an IBM ASIC which was used at some point which seemed
to have identical use and functionality to the 24RF08, according to 
Joe.

Thanks!


Phil


On Sun, Aug 25, 2002 at 03:36:49AM -0400, Dean L. Hedin wrote:
> I can only speak about the 600e as I have a broken mainboard here in front of 
> me as I write this.  I've looked it over and do not see a 24RF08 on the 
> board.  Other than the two flash devices that contain the BIOS, I see
> no other non-volatile memory devices on the board.
> 
> In any case, the lm-sensors warning posted at http://www.linux-thinkpad.org/
> indicates I2C being involved.   This is consistant with the 24C01A.  And I 
> know from other sources that this is where IBM security checksum information 
> is stored.  The 24C01A  that I speak of is not near any RAM device, it is near
> the BIOS flash chips.
> 

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