Changeset 2559

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Timestamp:
05/22/04 23:27:46 (5 years ago)
Author:
khali
Message:

Update 24RF08 status.

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  • lm-sensors/trunk/README.thinkpad

    r2406 r2559  
    25251) Sensors-detect accesses VPD information in the BIOS to identify IBM 
    2626   systems. If it finds the VPD structure (which is IBM-proprietary), 
    27    sensors-detect will print a message and exit, unless the system is 
    28    listed in a growing white-list. We add system signatures to the list 
    29    when users report that a given model has been tested to be safe. 
     27   sensors-detect will print a message and exit. This is a temporary 
     28   additional measure, which will be removed as soon as the other 
     29   measures have proven to be efficient. 
    3030 
    31 2) The sequence of probes in sensors-detect has been changed so that 
    32    24RF08 eeproms are not corrupted. This *should* prevent corruption 
    33    of 24RF08 eeproms in any non-IBM systems in most cases. 
     312) The probing command (quick write 0) has been replaced by a different 
     32   command (read byte) for addresses where eeproms are known to live. 
     33   This should prevent corruption of 24RF08 eeproms in any system, 
     34   IBM or not. A similar change was made to i2cdetect as well, although 
     35   no corruption was ever reported using this tool. 
    3436 
    35373) The i2c-piix4 module (the bus driver that is used for Intel PIIX4-based 
    …… 
    56582) lm_sensors won't run on most IBM systems because of these changes. 
    5759 
    58 3) IBM Thinkpads contain a proprietary Embedded Controller which 
     603) Most IBM Thinkpads contain a proprietary Embedded Controller which 
    5961   is used to access sensors. This controller is not on the SMBus, 
    6062   and IBM will not release the programming interface to the 
    61    controller. So lm_sensors isn't useful on Thinkpads anyway. 
     63   controller. So lm_sensors isn't useful on these Thinkpads anyway. 
    6264 
    6365You may want to try ACPI instead, it should let you get some information 
    6466about temperatures and fan status. 
    6567 
    66 As described above, our 2.6.5 release "blacklisted" all IBM 
    67 systems. We were planning to refine refine the system detection so that 
    68 only those models containing 24RF08's are blacklisted. But it looks like 
    69 we will not get sufficient cooperation from IBM to implement a reliable 
    70 blacklist. For this reason, we will now be using the other approach: 
    71 a "white list" of known-to-be-safe systems. This is the only safe way. 
     68As described above, our 2.6.5 release "blacklisted" all IBM systems. 
     69For a moment, we have been planning to refine the system detection 
     70so that only those models containing 24RF08's are blacklisted. After that, 
     71we planned to use a different approach: a "white list" of known-to-be-safe 
     72systems. In both cases, it would require continuous updates of a machines 
     73list. This would have been slow and inefficient. 
    7274 
    73 Systems will be added to the white list at a slow rate, on user report. 
    74 Basically, users wanting to use lm_sensors on their IBM systems, either 
    75 because they know for sure that the system doesn't have the 24RF08 chip, 
    76 or because they like playing with fire, have to bypass the securities we 
    77 have implemented, and then report (hopefully) success, then we add their 
    78 system signature to the white list. Note that this list is only 
    79 implemented in sensors-detect at the moment, not the i2c-piix4 bus 
    80 driver. 
     75The latest idea is to stop using the dangerous command for EEPROM 
     76addresses. That way, risks of corruption are reduced to zero. This was 
     77already done for user-space tools, as mentioned above. Once this will 
     78have been tested and we are sure that there are no drawbacks, we'll 
     79do the same on the kernel side in Linux 2.6. The change won't occur in 
     80Linux 2.4 however, because it implies changes to both i2c modules and 
     81lm_sensors modules. It is possible to use mismatching versions of 
     82these modules, and when doing so, the fix would become more dangerous 
     83than helpful. 
    8184 
    8285We do not have any reports of 24RF08 eeproms on non-IBM systems.