Red Hat Bugzilla – Bug 666462
[NVa5] Brightness (backlight) control madness on Lenovo W510
Last modified: 2014-03-31 19:46:06 EDT
Created attachment 471224 [details]
After upgrading from F13 to F14 backlight (brightness) control on Lenovo W510 notebook got totally mad. There are a couple of issues:
- after boot the display is too dark. I'm barely able to see the letters, but the brightness control shows me I'm at the max.
- curiously, after plugging/unplugging the power connector the display goes to very-very-max bright, that I'm used to from F13.
- BUT, after I try to take the brightness down just by one level I go back to pretty dark (like just after boot).
Attaching a couple of logs, please ask for more if I haven't supplied the right ones.
Created attachment 471225 [details]
gnome-power-manager --verbose output
As a regular user, executed `killall gnome-power-manager'.
Then `gnome-power-manager --verbose | tee gpm.log' (which is attached).
+ I've just noticed I can't find the brightness applet I've used in F13 + Gnome.
JFTR, Xorg server version:
Found this in /var/log/messages, if relevant:
thinkpad_acpi: Standard ACPI backlight interface available, not loading native one.
Tried booting into F13 kernel 126.96.36.199-66.fc13.x86_64, the brightness is at the max. But I'm unable to adjust it by the brigtness keys.
And the helper app prints a nonsense current value.
$ gnome-power-backlight-helper --get-brightness
$ gnome-power-backlight-helper --get-max-brightness
I had exactly this issue when I installed F14, but worked around it by using the proprietary binary blob from nvidia.
I believe the correct solution is this commit from upstream:
As this doesn't look as if it would break anything, maybe it could be added as a patch to Fedora's kernel.
This bug is probably related and the patch in there is also a viable workaround, iirc:
I can confirm that brightness is at the max with nvidia binary blob. Downside to that is that I can't manage brightness (it's always at the max).
I just removed the binary blob and built a new kernel using the above upstream patch. Brightness control now works as expected.
Note that rawhide isn't affected, probably because the patch already is upstream. (included in 2.6.37)
This should probably be rolled out as an update for F14.
This would probably also fix  (maybe it this even is a duplicate)
As the fix is a kernel patch, should this bug be reassigned to Fedora/kernel?
btw, you can also get brightness control when using the blob, by setting
Option "RegistryDwords" "EnableBrightnessControl=1"
in the "Device" Section of your xorg.conf
(In reply to comment #7)
> I just removed the binary blob and built a new kernel using the above upstream
This may be a total n00b question, but how do I apply this patch?
I am also experiencing this issue. When can we expect to see an updated kernel?
*** This bug has been marked as a duplicate of bug 625171 ***