Re: Laptop screen not turning off in ACPI S1

[Vibol Hou <vibol khmer cc>]

Just out of curiousity, I was reviewing the kernel proper for the code 
that is executed as the system enters suspend and it appears to be 
allocating a VT and switching to it to display debug messages.  This 
appears to be causing my screen to switch back on since I have a script 
that shuts off my display when I initiate sleep mode (script found at: 
http://ltswww.epfl.ch/~dsanta/resources/dell-i8500-linux).  I modified 
the script to work with 2.6.

My question is; is it necessary for the kernel to do all this terminal 
switching?  I'm tempted to patch the kernel to remove the 
allocation/switching/debug code but I'd like to know if this was done 
for a reason (other than to output the debug messages).

-Vibol

Alexandre Oliva wrote:
> On May  7, 2004, Vibol Hou <vibol khmer cc> wrote:
>
>
> > When I issue an echo -n "1" > /proc/acpi/sleep, my laptop (Dell Lat
> > C400) enters the state, but the laptop screen does not turn off.  Is
> > there a way of getting the laptop screen to turn off in S1?
>
>
> The ugly work around I found on my Dell Inspiron 8000 was to run:
>
> sleep 5; echo ...
>
> and then close the lid, such that the display is turned off.  Then,
> when you enter the sleep state, it remains so.
>
> Yeah, yuck :-/  But it works :-)