View source for Problem with LCD backlight remaining on during ACPI sleep

==Problem description==
On some models the LCD backlight remains on during ACPI sleep.

==Affected Models==
*ThinkPad {{390X}} with kernel boot option ACPI=force
*ThinkPad {{A30}}
*ThinkPad {{A31p}}
*ThinkPad {{T30}}
*ThinkPad {{X31}},{{X32}}
*ThinkPad {{R51}}
(according to the relevant bug on the Kernel bug tracker ([http://bugzilla.kernel.org/show_bug.cgi?id=2576 bug 2576]))

==Partial solution==
If the ThinkPad has a radeon video chip, then switching off the light with the command
  radeontool light off
will work, but only in a text-mode virtual terminal.  If X is running, the light apparently comes back on when the kernel switches to text mode prior to sleeping.  The solution in that case it to switch to a text mode console first.

 logger "Software suspend to ram."
 FGCONSOLE=`fgconsole`
 chvt 1
 radeontool light off
 echo -n 3 >/proc/acpi/sleep
 logger "Woke up from suspend."
 radeontool light on
 chvt $FGCONSOLE

Improvements are clearly possible. :-)

On the X32, at least, the bios will switch off the screen by default on a lid close, and suspending to ram interrupts this, and the screen will turn back on.  This can be fixed by simply adding "sleep 5" before "echo -n 3 > /proc/acpi/sleep".  The suspend will take longer, but the screen will remain off.

A similar script can be found on the [[How to configure acpid|acpid configuration HOWTO]] page.

{{NOTE|In Debian Testing (and maybe other Distributions/Debian versions using the hibernate-tool) you can simply uncomment the "RadeonTool yes" line in /etc/hibernate/ram.conf}}

==Using Powersaved==

If you use powersaved you can just edit the two scripts prepare_suspend_to_ram and restore_after_suspend_to_ram which are stored in /usr/lib/powersave/scripts/

add two lines to prepare_suspend_to_ram nearly at the end of the script:

  # insert the next two lines:
  chvt 1
  radeontool light off
  # this changes to a console nr. 1 and switches the light off
  
  progress_finish
  $SCRIPT_RETURN $EV_ID 0 "prepare_sleep finished successfully for $1"
  EXIT 0

and to restore_after_suspend_to_ram
  # insert the next two lines:
  radeontool light on
  chvt 7
  # this switching the light on and changes to display #7 (where the x-server runs) - 
  #you can change it to another display if you want... 
  #(the way doing this with a variable like in the script above doesn't work, because it can't be stored between
  #the two different scripts.
  
  # $SCRIPT_RETURN is called in restore_after_sleep.
  EXIT 0

Than you can suspend to ram with /usr/bin/powersave -u or just configure powersaved in a way that it suspends to ram when your notebook is closed. (As a frontend kpowersave is recomended).

==Using s2ram==

Just using the s2ram command from the uswsusp (Userspace Suspend) package should do the trick by appending the "-r" option (-r, --radeontool: turn off the backlight on radeons before suspending.).

==Editing menu.lst in OpenSuse==

A simple change in a start-up file in OpenSuse 11.3 corrected this problem

1. Open a terminal and type gnomesu gedit /etc/grub/menu.lst. When prompted, type root password and click OK. 

2. Gedit opens with the menu.lst file displayed. Down the page a bit, there are several sections that begin with "###Don't change this comment" 

3. The first section gives details for the default boot operating system. Somewhere in this long spec, find "vga=0x314" or vga=(something specific to your system). 

4. Just before or after this vga spec, type "nomodeset" separated from the vga spec by a space.

5. Save the file and reboot. In OpenSuse, suspend/resume now works normally.