Re: Brightness and Contrast controls on iMacs
On Fri, 2003-01-10 at 11:14, Scott McMahan wrote:
> I'm looking for a way to adjust the screen settings on my iMac. I've
> search the list/newsgroups and the answers I've found don't work on CRTs
> (fblevel) or don't really address the right problem (xgamma). Is there
> a utility available to handle this problem? If not, is anyone working
> on one? If not, can anyone help point me in the right direction so I
> can start working on one?
My understanding is that the screen (brightness, contrast, power
management and geometry) on iMacs is handled by tapping an i2c
device. On some iMacs, it's on one of the PMU i2c busses, I'm not
too sure about older iMacs, it's either on Cuda or on the video
card's i2c bus.
There is no real support for PMU i2c currently in the kernel,
though you can eventually try to feed PMU i2c commands via
/dev/adb, though I'm not completely sure you'll get the replies
properly, that's something I have to investigate.
Most of the informations about the device itself can be found
in Darwin's source AppleOnboardDisplay module.
Ben.
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