From noreply at ubuntu.com Fri Apr 21 16:29:25 2017
From: noreply at ubuntu.com (Ubuntu Wiki)
Date: Fri, 21 Apr 2017 16:29:25 -0000
Subject: =?utf-8?q?=5BUbuntu_Wiki=5D_Update_of_=22Kernel/Debugging/Backlight=22_by?=
=?utf-8?q?_ckrainey?=
Message-ID: <20170421162925.336.9881@mangaba.canonical.com>
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The "Kernel/Debugging/Backlight" page has been changed by ckrainey:
http://wiki.ubuntu.com/Kernel/Debugging/Backlight?action=diff&rev1=34&rev2=35
* If using a v3.13.x+ series kernel, reboot with just kernel parameter video.use_native_backlight=1 and make a comment on if you can now alter the backlight with hotkeys or a brightness applet.
* If your backlight hotkeys are Fn+Left and Fn+Right, add kernel parameter atkbd.softraw=0 to /boot/grub/menu.lst . Then, switch to any console, e.g. Ctrl+Alt+F1, login by root account and execute:<
> {{{showkey -s}}} <
> <
> Then, press Fn+Left and Fn+Right key to check the code that shows up on screen. Post the results to the report. For example: <
> <
> Fn+Left: <
> 0xe0 0x4c 0xe0 0xcc <
> <
> Fn+Right: <
> 0xe0 0x54 0xe0 0xd4
+
+
+ SEE ALSO: [[https://help.ubuntu.com/community/ScreenBacklight|ScreenBacklight]]
+
+
+
=== Intel HD Graphic Controllers ===
With an Intel HD Graphic Controller if passing kernel parameter acpi_backlight does not work, or it freezes and/or crashes, one may try adjusting which backlight interface is used by creating a new file in {{{/usr/share/X11/xorg.conf.d/80-backlight.conf}}} and paste into it the following code: {{{