Re: [lcd4linux] Display for a router

[Ognjen B. <og...@ma...>]

Stefan Bachmaier wrote:

> On Sat, 22 Oct 2005 12:59:01 +0200, <sp...@fr...> wrote:
>
>> Hi,
>>
>> I am using an old PC as router for my home network.
>> At the moment it is standing beside my desktop pc and I have a 
>> monitor  attached to it.
>>
>> Now I wanted to place the router some where elses and I also wanted 
>> to  remove the monitor from it.
>>
>> I thought a small LCD display would be great to display the status 
>> of  the box.
>>
>> Now my question is:
>>
>> Is it possible to display the "power off" message on a LCD? Or at 
>> what  stage of the shut down is the driver unloaded, so that no 
>> further  display is possible?
>>
>> I would like to have a message on the LCD when it is safe to power 
>> off  the router, without destroying my installation.
>>
>> Thanks for reading,
>> FReAK
>
>
> There's a Linuxfocus article about a Shutdown-Led:
>
> http://linuxfocus.org/English/January2001/article186.shtml
>
> Or get a PC with ATX Power, which shuts itself down.
>
> However you could re-write the lcd4linux code where the 'Goodbye' 
> message  is displayed, when the program is stopped.
>
> Greetings, Stefan
>
>
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Another idea is the use the HD44780 kernel driver, this will let to 
write to the LCD display using the echo command (i.e. echo "Sutdown 
complete" > /dev/lcd).

As its a kernel rather then a userspace program it does not get unloaded 
(particulary if you do not compile it as a module) meaning that you can 
write to the LCD at any point in the shutdown stage.
 From hereon you just modify your init shutdown script to echo whatever 
you want at which ever point (so you could have "Shutting down", "Stage 
1 complete","Stage 2 complete"....etc... "Shutdown complete").

You can also  use this is bootup to check if your interfaces came up etc...