[ltp] final status report (further testing not needed)

[Henrique de Moraes Holschuh]

Again, thanks to all that reported in with the data for their machines.

Note that the ammount of models not affected is enough to set the group of
affected models apart in time (i.e. we have a lower bound, the TP-1R and
TP-1V, and higher bounds, the TP-79 and TP-7C), so it is very unlikely that
we will find any other ThinkPads that suffer from the same bug.

Some data was found that is not in the FW bug report: all ThinkPads except
those hit by the bug normally boot with the fan set to 0x80 (mode: auto).
This applies only to ThinkPads wich use the EC 0x2F register for fan
control.

The final report is in ThinkWiki:
http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Bug:_Fan_control_loop_status_is_not_initialized

And it is reproduced below for your convenience, and to help those searching
this in the mailinglist archives:

Bug: Fan control loop status is not initialized

    * Severity: low
    * Linux annoyance level: low
    * Windows annoyance level: unknown
    * Fix: unknown status at this time, usually worked around by ACPI DSDT.

    * Models affected (confirmed):
          o TP-1Y (T43, T43p), TP-78 (R51e), TP-76 (R52), TP-70 (R52, T43) 
    * Models NOT affected (confirmed):
          o TP-7C (R60), TP-79 (T60/p), TP-1A (T23), TP-1G (A31), TP-1V (R51), TP-1R (T40/p,T41/p,T42/p,R50/p,R51) 

The EC does not correctly initializes its 0x2f (fan control) register, so
ibm-acpi cannot determine the correct status of the fan control until
something writes to the fan control register for the first time.

Writes to the fan control register in their ACPI DSDT methods provides a
work-around. This usually fixes the issue during suspend and wakeup.

So far, there are only reports of wrong readings of 0x07, no other wrong
value has been observed. Note that 0x07 might be a correct value if the
system is in emergency fan mode (level 7). 

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh