Ambient light level sensor in Fedora 8???

Nataraj incoming-fedora-list at
Sun Nov 11 20:53:07 UTC 2007

Hi Sam,

Is it possible that this is a power saving feature in the bios of your
laptop that never worked before because your F7 configuration had power
saving features disabled?


On Sun, 2007-11-11 at 13:13 -0500, Sam Varshavchik wrote:
> I thought that I was going nuts at first, but I confirmed this after some 
> experimentation: after upgrading one of my laptops to Fedora 8, the LCD 
> backlight seems to autoadjust itself according to the ambient light level in 
> the room. This did not happen in Fedora 7.
> I left the laptop running, then came back a few minutes later with the 
> lights off in the room, and the laptop's screen was about half at its usual 
> brightness. I thought that it was some screensaver at first, but it wasn't. 
> Uh-oh, is my backlight busted? I turned on the lights in the room, so I 
> could see better, and immediately the LCD went up to its full brightness 
> level. I turned the lights off, and a few seconds later the display dimmed 
> to about a 50% level. WTF?
> This is a no-name brand laptop. I have a small widget directly above the 
> screen that is labeled with a small etched picture of a microphone. That's, 
> apparently, my laptop's built-in microphone, which I never used. I 
> discovered that if I cover up the entire microphone sensor, that triggers 
> the backlight to dim to half power. Looks like I have an ambient light 
> sensor in there. News to me -- the laptop's ~2 years old, and I never knew 
> about it until now. It apparently didn't do anything in F7, neither does the 
> dual-booted Win XP pay any attention to the came, but in F8 it came alive 
> and made its presence known.
> Does anyone know anything about this, and, specifically, if there's anything 
> in F8 Gnome that lets me tweak this sensor's settings? I don't see anything 
> going to /var/log/messages when I play with the sensor. A brief search 
> didn't find anything. I don't see anything in the Gnome power management 
> menu, except the usual global backlight levels for AC Power and Battery 
> modes, and I can trigger this sensor both on AC Power, and battery power, 
> apparently.
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