[ltp] tpctl on T61 needs force_io=1 since kernel 2.6.29

[Henrique de Moraes Holschuh]

On Thu, 26 Mar 2009, Kai Weber wrote:
>> Up until now the problem was only present on the new models, T400, T500 
>> and X200 (according to thinkwiki)
>> Did you update your bios recently Kai? Maybe Lenovo introduced the 
>> faulty setting into the BIOS of the T61 as well....
>
> No recent BIOS update on my side. As I wrote, it seems to be a change  
> introduced by kernel 2.6.29. 2.6.28 works without force_io=1.

The kernel just decided to actually pay attention to IO reservation tables,
so it is not a kernel bug.  It is a BIOS bug, that the kernel decided that
it didn't want to ignore anymore by default for safety reasons.

In this case it isn't dangerous, so you can force_io=1.  But on the case of
some i2c drivers that were fighting over the BIOS for control (for some
other machines, not thinkpads), it _was_, and the new behaviour would block
the i2c driver from loading.

-- 
  "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