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["Christopher M. Penalver" <christopher.m.penalver@xxxxxxxxx>]

** No longer affects: pm-utils (Ubuntu)

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https://bugs.launchpad.net/bugs/955046

Title:
  Screen backlight is OFF when resuming from suspend with vgaswitcheroo
  controlled cards

Status in The Linux Kernel:
  Confirmed
Status in linux package in Ubuntu:
  Incomplete

Bug description:
  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 when resuming from 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.

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