fsck recoveries, configuration

[Gary Aitken]

On 08/17/12 21:17, Polytropon wrote:
> On Fri, 17 Aug 2012 20:44:10 -0600, Gary Aitken wrote:
>> On 08/17/12 19:05, Polytropon wrote:
>>>> 2.  When my machine hung (could not rlogin or ping), I powered
>>>> off and rebooted.
>>>
>>> Does the machine have a "soft power button" and it is configured
>>> to issue a "shutdown -p now" (which is quite common)? When you
>>> have access to the machine, try that. Even if the machine does
>>> not accept network logins, this mechanism might still work.
>>
>> Hmmm.  It has a "soft" power button; have to hold it down 5 sec
>> or so to power off.
> 
> That's the "override time" for a "hard power off". If you only
> press it once, it should issue "shutdown -p now", but of course
> this only works if the system is still responding. Even if the
> keyboard input and screen output, as well as networking services
> stopped to work, this _might_ still be effective.

>> Those things can be configured to issue a command that will actually
>> get executed without a login?
> 
> Sure, it has been working for many years. Check the BIOS setup,
> some machines can be configured to what the button does. The
> default setup of FreeBSD should perform the correct action via
> ACPI.
> 
> In the past, it also worked with APM. In that case, /etc/apmd.conf
> would contain the command executed when the button was pressed.
> On APM-capable machines, the PSU would be switched off, just like
> today's ACPI-based systems. Of course that only works with ATX
> power supplies, the AT ones usually had a mechanical switch.

Ah, I see.  The driver raises a signal the system can respond to.

>> I assume you're talking about a bios option?  How does that work?
> 
> I've seen BIOS setups allowing different actions for the button,
> from "go to sleep" to "soft power off" or "hard power off". That
> action (hard power off) is taken when pressing the button for
> about 5 seconds. The OS can NOT deal with that case.
> 
>> sounds like magic of some sort...  Or is this a whole login
>> sequence with the shutdown at the end?
> 
> No, it's a system action using ACPI. No magic involved. :-)

I'll look at it next time I reboot.  Reading the bios manual, it looks like acpi 2.0 support is disabled by default, which may be where it is; otherwise I don't see anything obvious.  Thanks.