screen brightness under lucid

[Reinhold Rumberger]

On Saturday 08 May 2010, pkaplan1 wrote:
> On Friday, May 07, 2010 09:25 Reinhold Rumberger wrote:
> > On Friday 07 May 2010, pkaplan1 wrote:
> > > I'm running lucid on a Thinkpad T41.  Never had a display
> > > problem until the new install.
> > > 
> > > As soon as I start KDE (not other WMs), the screen is dimmed
> > > to about 50% of brightness.  I can brighten manually, but
> > > it's a PITA.
> > > 
> > > Has anyone observed this or found a solution?
> > 
> > My Laptop does the same thing when on battery - that's how I set
> > it up. Check your power management settings, they might be
> > causing this.
> 
> I checked this.  PM is configured to set the screen to full
> brightness when on AC power (as previously).  Changing these
> settings didn't affect the behavior.
> 
> My original description is wrong, however.  The behavior affects
> all window managers...whenever I start an X session, the screen
> is dimmed to about 50%. Even switching between running WMs on
> different virtual terminals causes the screen to dim to 50%. 
> Does this sound like a driver problem?  I'm running an ATI M7500
> video card, but I didn't notice the behavior with the LiveCD??
> Paul

My Dell's BIOS has an option for screen brightness that has a similar 
effect. It seems to confuse whatever is responsible for setting the 
screen's brightness. It seems that some sort of default brightness is 
stored at boot time and restored whenever the screen is switched back 
on. I haven't found a fix for this yet, and it hasn't bothered me 
enough to search particularly hard...

  --Reinhold