Re: current kernel + userland just resets

[Simon Truss <simon%bigblue.demon.co.uk@localhost>]

Riccardo Mottola wrote:
> Hi,
>
> On Sep 26, 2011, at 8:34 AM, Riccardo Mottola wrote:
> > > Now it just happened again. There was no reboot, the machine just hung... 
> > > stopped responding. Locally, the machine has a black screen and doesn't respond 
> > > to even simple stuff like caps-lock. So I need to keep the power button pressed 
> > > and recycle it.
> > This is sounding more like a failing PSU or maybe leaky caps on the 
> > motherboard, causing PWR_OK to be de-asserted and the machine to hard-hang, 
> > requiring a full power-cycle.
> true, but it is a laptop with a new battery... It worked very reliably 
> until... the last kernel update. Of course, coincidences happen... 
> however....

I've come across several laptops (from different manufacturers) that 
randomly switch off, the problem has always been traced to a faulty lid 
switch (the contactless magnetic/hall effect type, not the old style 
microswitch ones). Change the OS and the problem goes away or the 
symptom changes. Similarly disable the power management and the problem 
stopped. Could it be power management shutting down the computer? 
getting the switch fixed usually requires a keyboard replacement under 
the warranty.

all the best,

Simon