Re: Power cut in management

[Marco <marco.stornelli@coritel.it>]

Jamie Lokier ha scritto:
> David Woodhouse wrote:
>> On Sat, 2008-10-18 at 13:56 +0100, Jamie Lokier wrote:
>>> Trouble is, that's not suitable for a dashboard unit where users plug
>>> in their own media card.
>>>
>>> Marco didn't say if the SD card is for users to plug in their own
>>> media, or if it's internal storage for the device.
>> True, but the situation is different for a removable card. Firstly, it's
>> unlikely to be mission-critical; the device will still operate without
>> it. Secondly, even the most naïve of users knows that these things are
>> disposable.
>>
>> It's different if you're building a black box around them, with one of
>> these things inside.
> 
> I agree, this is very good advice.
> 
> -- Jamie
> 
Thank you very much for your response. The sdcard, however, it's for the
user so I haven't control on it, I think probably it will be FAT. Jamie
you said to manage the situation with an interrupt, I agree. My first
plan was (more or less) to have an application in user space that it
checks the interrupt (UIO driver ?) and simulates a console command to
do a clean shutdown. Then in the kernel routine I do something to cut
the power definitely. For my environment (about the time) it's possible
even in relation with the "emergency power". The only problem is: what
happens if before I install the irq handler the user turn off the
system? I mean I can't "loose" the interrupt. In this case it'd be like
a spurious interrupt from system point view. Let me know if I'm wrong.
Thanks.