Red Hat Bugzilla – Bug 458881
Adjusting screen brightness fails on VGN SZ2M/B
Last modified: 2010-06-28 09:46:17 EDT
Description of problem:
On a Sony VGN SZ2M/B the brightness applet does not change the screen's brightness. After changing it manually and restarting X, the applet works flawlessly.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Boot up F9 on a VGN SZ2M/B
2. Login as user
3. Try to change screen brightness with 'Power Manager Brightness Applet' (fails!)
Changing screen brightness
After changing the brightness manually with 'echo 1 > /sys/class/backlight/sony/brightness' and restarting the X-server, the brightness applet works as expected
This Problem got even worse with Fedora 10:
Touching the brightness applet freezes X. After writing something to '/sys/class/backlight/sony/brightness' and restarting X, the applet says 'Cannot connect to gnome-power-manager'.
Does this still happen with the version in fedora rawhide, or the version of the Fedora 11 beta live cd?
Ok, the freezing X problem disappeared in F11. But changing the brightness will only work if you write some value between 0 and 7 to /sys/class/backlight/sony/brightness _before_ you use the applet or hotkeys (doesn't matter what value). Otherwise you are stuck with the lowest brightness level.
Adding "echo 7 > /sys/class/backlight/sony/brightness" to rc.local works for me!
Sony Vaio BZ11XN
Can't set backlight, it's stuck at 100 % all the time
The LCD baclight is too strong at 100 %, killing battery life, and when using AC it makes looking at the screen painful after a few minutes, too much light.
Installed Fedora 11 from DVD, 64-bit version
The gnome power management panel does not have anything to set the backlight, the function keys for backlight have no effect.
Using xbacklight after installing it says :
[root@blackbird ~]# xbacklight -set 50
No outputs have backlight property
Trying to modprobe sony-laptop says :
[root@blackbird ~]# modprobe sony-laptop
WARNING: Deprecated config file /etc/modprobe.conf, all config files belong into /etc/modprobe.d/.
When looking for a module on the disk I can see I have a :
But I updated my kernel it seems on the last update :
[root@blackbird ~]# uname -a
Linux blackbird 126.96.36.199-213.fc11.x86_64 #1 SMP Tue Jul 7 21:02:57 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
And the module is not there, so perhaps the sony-laptop is in the kernel ? (no idea how to check that)
(In reply to comment #3)
> Adding "echo 7 > /sys/class/backlight/sony/brightness" to rc.local works for
Smells like a kernel problem.
I have the same problem. As soon as Fedora 11 pushed out kernel [188.8.131.52-43.fc11.x86_64] my laptop brightness failed.
I had a similar experience when I upgraded to 2.6.30 during the RC test cycle, the brightness applet failed then, however the developers said it wasn't a sony-laptop problem since other users were fine, and the key events were being notified by the sony-laptop module.
I get these reported by dmesg when I press the Fn-brightness keys:
sony-laptop: sony_nc_notify, event: 0x11
sony-laptop: sony_nc_notify, event: 0x3b
sony-laptop: sony_nc_notify, event: 0x10
sony-laptop: sony_nc_notify, event: 0x3b
Someone on #fedora-kernel said kernel fix to loosen the validation/tolerance was underway, but I thought I'd post this anyway for the record.
also in vgn-aw21m/vgn-aw11n all blu key are unuseable (excuse my english please :-(
Is bug 519105 a duplicate of this bug report ?! Can you test if adding the kernel boot parameter 'nomodeset' fixes anything !?
It now works.
I have installed Fedora 12. The problem was still there.
But to fix the problem, all I had to do was edit the menu.lst
boot config file, and add the following to the kernel line :
After a reboot, when I press the Fn + Light Up/Down keys on
the Sony BZ11XN it now works nice.
(In reply to comment #8)
> Is bug 519105 a duplicate of this bug report ?! Can you test if adding the
> kernel boot parameter 'nomodeset' fixes anything !?
acpi_backlight=vendor fixed my problem
nomodeset had no impact nor use.
This fixed it for me too, Sony Vaio BZ12XN. No need to use the nomodeset option.
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Still does not work on my Acer Aspire 5740 notebook.