Comment 0 for bug 955046

Using vgaswitcheroo to disable the integrate or discrete card could lead to some troubles when resuming from suspension (to RAM or disk as well). Basically, the computer monitor backlight could be not be turned on again on suspension.

To me it happens this:
 - I disable the integrated card
 - Suspend
 - Resume: no monitor backlight is on

At this point doing what mentioned below fix the issue, but it must be done by SSH or by memory :):
  echo DIGD > /sys/kernel/debug/vgaswitcheroo/switch
  echo OFF > /sys/kernel/debug/vgaswitcheroo/switch

So, the easiest and clean fix should be to add a sleep.d script something like:

#!/bin/sh

if [ -e /sys/kernel/debug/vgaswitcheroo/switch ]; then
  case "$1" in
    hibernate|suspend)
      echo ON > /sys/kernel/debug/vgaswitcheroo/switch
      ;;
    thaw|resume)
      echo OFF > /sys/kernel/debug/vgaswitcheroo/switch
      ;;
  esac
fi

This would fix the issue for vgaswitcheroo users and won't touch the others.