Re: Laptop screen not turning off in ACPI S1

[Luciano Miguel Ferreira Rocha <strange nsk no-ip org>]

On Sat, May 08, 2004 at 01:11:58PM -0700, Vibol Hou wrote:
> 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).

Terminal switching, yes, in most cases. Debug code, no, and I think it can
be turned off by writing to the proper file in /proc or suspending with
the proper flags. I don't recall which one and what, as  it changed a few
times. Maybe there's some documentation, or at least the kernel source.

Regards,
Luciano Rocha