** Description changed:

- After kernel update the backlight on my Asus eeepc 1005px becomes off
- during boot up. I can see the login screen if I point light to the
- screen. The backlight is not reacting on brightness adjustment keys. The
- backlight starts working only if I close and open the laptop lid.
+ == SRU Justification ==
+ Commit 78f3ac76d9e5 ("platform/x86: asus-wmi: Tell the EC the OS will
+ handle the display off hotkey") causes the backlight to be permanently off
+ on various EeePC laptop models using the eeepc-wmi driver (Asus EeePC
+ 1015BX, Asus EeePC 1025C).
+ 
+ == Fix ==
+ * 1dd93f87 (platform/x86: asus-wmi: Only Tell EC the OS will handle
+ display hotkeys from asus_nb_wmi)
+ 
+ This patch addes a .wmi_backlight_set_devstate quirk for specific
+ models to make asus_wmi_set_devstate(ASUS_WMI_DEVID_BACKLIGHT, 2, NULL)
+ conditional.
+ 
+ Only X/D contain the commit that introduce this issue (78f3ac76), this
+ patch can be cherry-picked into D.
+ 
+ For X, it needs some content adjustment to add quirks only to those
+ models that exist in Xenial tree.
+ 
+ == Test ==
+ Test kernels could be found here:
+ https://people.canonical.com/~phlin/kernel/lp-1837117-eeepc/
+ 
+ Bug reporter has verified that this fix works as expected on X.
+ 
+ == Regression Potential ==
+ Low, quirks limited to specific ASUS laptops and by far there is no
+ further change to this in upstream kernel.
+ 
+ 
+ == Original Bug Report ==
+ After kernel update the backlight on my Asus eeepc 1005px becomes off during 
boot up. I can see the login screen if I point light to the screen. The 
backlight is not reacting on brightness adjustment keys. The backlight starts 
working only if I close and open the laptop lid.
  
  I have tried to:
  * echo 10 > /sys/class/backlight/acpi_video0/brightness
  * echo 125 > /sys/class/backlight/intel_backlight/brightness
  * vbetool dpms on
  * pass "acpi_backlight=vendor" kernel parameter
  * install gdm instead of lightdm
  * create /usr/share/X11/xorg.conf.d/80-backlight.conf with content 
recommended in Kernel/Debugging/Backlight Wiki article
  with no luck.
  
  The backlight works fine if I pass "acpi_osi=" kernel parameter, the
  brightness is adjusted by keys, but the applet does not react to
  adjustments.
  
  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: linux-image-4.4.0-145-generic 4.4.0-145.171
  ProcVersionSignature: Ubuntu 4.4.0-145.171-generic 4.4.176
  Uname: Linux 4.4.0-145-generic x86_64
  ApportVersion: 2.20.1-0ubuntu2.18
  Architecture: amd64
  CurrentDesktop: XFCE
  Date: Thu Jul 18 22:30:44 2019
  InstallationDate: Installed on 2019-02-17 (151 days ago)
  InstallationMedia: Xubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 
(20160719)
  SourcePackage: linux-signed
  UpgradeStatus: No upgrade log present (probably fresh install)

** Summary changed:

- Laptop backlight is off after system boot up
+ EeePC 1005px laptop backlight is off after system boot up

** Changed in: linux (Ubuntu Disco)
       Status: New => In Progress

** Changed in: linux (Ubuntu Disco)
     Assignee: (unassigned) => Po-Hsu Lin (cypressyew)

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https://bugs.launchpad.net/bugs/1837117

Title:
  EeePC 1005px laptop backlight is off after system boot up

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