I did some more testing and I nailed the change to the 3.15.7 kernel update.
I must have confused versions in my initial report.
Anyways, looking throught the changelog for that kernel version I found
this changeset :
commit be907c8468c9f47882036109ba550cd2748b86a0
Author: Alex Deucher <alexander.deuc...@amd.com>
Date: Tue Jul 15 09:48:53 2014 -0400
drm/radeon: set default bl level to something reasonable
commit 201bb62402e0227375c655446ea04fcd0acf7287 upstream.
If the value in the scratch register is 0, set it to the
max level. This fixes an issue where the console fb blanking
code calls back into the backlight driver on unblank and then
sets the backlight level to 0 after the driver has already
set the mode and enabled the backlight.
bugs:
https://bugs.freedesktop.org/show_bug.cgi?id=81382
https://bugs.freedesktop.org/show_bug.cgi?id=70207
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Tested-by: David Heidelberger <david.heidelber...@ixit.cz>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
This modified the way the radeon module handles default backlight values.
Looking through the first bug report I found out about the "radeon.backlight"
kernel option.
Adding "radeon.backlight=0" to grub command line fixed the display brightness
issue.
** Bug watch added: freedesktop.org Bugzilla #81382
https://bugs.freedesktop.org/show_bug.cgi?id=81382
** Bug watch added: freedesktop.org Bugzilla #70207
https://bugs.freedesktop.org/show_bug.cgi?id=70207
** Also affects: xserver-xorg-driver-radeonhd via
https://bugs.freedesktop.org/show_bug.cgi?id=81382
Importance: Unknown
Status: Unknown
--
You received this bug notification because you are a member of Ubuntu-X,
which is subscribed to xorg in Ubuntu.
https://bugs.launchpad.net/bugs/1363623
Title:
[ASUS-A7K laptop] screen brightness dimmed after kernel update
To manage notifications about this bug go to:
https://bugs.launchpad.net/xserver-xorg-driver-radeonhd/+bug/1363623/+subscriptions
_______________________________________________
Mailing list: https://launchpad.net/~ubuntu-x-swat
Post to : ubuntu-x-swat@lists.launchpad.net
Unsubscribe : https://launchpad.net/~ubuntu-x-swat
More help : https://help.launchpad.net/ListHelp
