[ltp] Random rfkill toggling on an X201s

[Henrique de Moraes Holschuh]

On Sat, 25 Jun 2011, Nathaniel Smith wrote:
> I figure this is probably either some flaky hardware, or some kind of
> kernel bug. Does anyone have any idea how to debug further?

It is flaky hardware.

> 22785.447378: bluetooth transmitter disappears from the USB bus

This can only happen when the hardware kill switch is triggered (or if you
tell the EC to do it, perhaps.  Still, the kernel does _not_ know how to do
that, so...)  I'd check that switch and its wiring for damage.

> There seem to be two hardware rfkill controls -- a slider switch on
> the left side of the case, and the Fn-F5 combo on the keyboard. The
> slider seems fairly solid mechnically -- I tried jiggling it around to

It can caused by cold solder.  Which is going to be a pain to fix if it is
in the planar card.  Usually one would reflow the entire thing just in case.

> Alternatively, does anyone have any suggestions on what might be going
> wrong hardware-wise? E.g., I could pull out the slider switch and
> reseat it, but I don't know that that would help any...

You can try to reflow the solder in the switch and its wiring, and also
check the wiring itself.

-- 
  "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