Unable to set brightness in Power Management

Adam Williamson awilliam at redhat.com
Mon Mar 15 19:42:14 UTC 2010


On Tue, 2010-03-09 at 17:21 -0800, Adam Williamson wrote:
> On Tue, 2010-03-09 at 23:13 +0000, Tommy He wrote:
> > The brightness shortcuts don't work, either. There is no slider in the
> > place where it used to be. gnome panel applet reported unable to
> > acquire the laptop LCD screen brightness information.
> > 
> > No matter I use Nvidia binary driver from rpmfusion nor nouveau
> > gallium3d driver, the situation remains the same: No way to adjust the
> > brightness.
> > 
> > Running on Fedora 13 Alpha LiveCD does not make any difference. No
> > such problem with previous Fedora release. I used to run the same
> > nivida binary driver on Fedora 12. Slider was there.
> > 
> > http://www.smolts.org/client/show/pub_0b8133aa-815e-4c11-9e5f-f5ca20f88bb6
> > 
> > My dmesg message below:
> > 
> > http://pastebin.ca/1830842
> > 
> > I will see what happens on other laptop.
> 
> I believe screen dimming is usually implemented in the ACPI layer, not
> in the graphics driver. It's nothing to do with the _graphics card_ -
> it's the brightness of the monitor itself that's changed. In the same
> way as nothing changes in what the graphics card is doing if you just
> reach out and hit the brightness control on your desktop monitor.
> 
> So the fact that you didn't see it in the past with the same video card
> driver doesn't really matter. This is likely a kernel bug of some kind.
> Could you try booting with various different kernels to see if you can
> isolate exactly when it broke?

Just saw a changelog go through which probably explains this:

-----

 gnome-power-manager-2.29.91-2.fc13 (FEDORA-2010-4350)

Update Information:

This update re-enables brightness changing support through HAL for some
graphic cards.

* Thu Mar 11 2010 Bastien Nocera <bnocera at redhat.com> 2.29.91-2
- Update to 2.29.91
- Revert HAL removal, or some machines wouldn't have brightness
  handling any more

-----

so yeah, it was a g-p-m change, update your g-p-m and it should work
again.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Fedora Talk: adamwill AT fedoraproject DOT org
http://www.happyassassin.net



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